title: QT5.5 'failed to load platform plugin "cocoa"' - MacOS 10.9
body: <p>I am using ete3 (tree visualization) library, which has PyQT as one of its dependencies. When I try to render a tree (tree.render), which access Qt libraries, it fails and gives me the error:</p>
  
  <pre><code>"This application failed to start because it could not find or load the Qt platform plugin "cocoa".
  Available platform plugins are: cocoa, minimal, offscreen.
  Reinstalling the application may fix this problem.
  Abort trap: 6"
  </code></pre>
  
  <p>I have checked the <a href="https://stackoverflow.com/questions/25188153/this-application-failed-to-start-because-it-could-not-find-or-load-the-qt-platfo">existing discussions</a> and also the <a href="http://doc.qt.io/qt-5/osx-deployment.html#qt-plugins" rel="nofollow noreferrer">Qt documentation</a> regarding this, but changing the plugin path in qt.conf didn't help.</p>
  
  <pre><code>  Process:         Python [22195]
    Path:            /Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python
    Identifier:      Python
    Version:         2.7.6 (2.7.6)
    Code Type:       X86-64 (Native)
    Parent Process:  bash [8443]
    Responsible:     eclipse [8418]
    User ID:         502
  
    Date/Time:       2016-03-15 16:30:05.179 +1300
    OS Version:      Mac OS X 10.9.5 (13F1603)
    Report Version:  11
    Anonymous UUID:  0BEE0024-9A4E-5B22-7A56-EB2C12CF1FC2
  
  
    Crashed Thread:  0  Dispatch queue: com.apple.main-thread
  
    Exception Type:  EXC_CRASH (SIGABRT)
    Exception Codes: 0x0000000000000000, 0x0000000000000000
  
    Application Specific Information:
    abort() called
  
    Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
    0   libsystem_kernel.dylib          0x00007fff8f7bf866 __pthread_kill + 10
    1   libsystem_pthread.dylib         0x00007fff89c2a35c pthread_kill + 92
    2   libsystem_c.dylib               0x00007fff92067b2e abort + 125
    3   org.qt-project.QtCore           0x0000000103e60ab9 qt_message_fatal(QtMsgType, QMessageLogContext const&amp;, QString const&amp;) + 9
    4   org.qt-project.QtCore           0x0000000103e62487 QMessageLogger::fatal(char const*, ...) const + 231
    5   org.qt-project.QtGui            0x000000010388d527 QGuiApplicationPrivate::createPlatformIntegration() + 6359
    6   org.qt-project.QtGui            0x000000010388d54b QGuiApplicationPrivate::createEventDispatcher() + 27
    7   org.qt-project.QtCore           0x000000010401d4ec QCoreApplication::init() + 204
    8   org.qt-project.QtCore           0x000000010401d407 QCoreApplication::QCoreApplication(QCoreApplicationPrivate&amp;) + 39
    9   org.qt-project.QtGui            0x000000010388a9ee QGuiApplication::QGuiApplication(QGuiApplicationPrivate&amp;) + 14
    10  org.qt-project.QtWidgets        0x00000001044689ee QApplication::QApplication(int&amp;, char**, int) + 206
    11  QtGui.so                        0x0000000103365a33 init_type_QApplication(_sipSimpleWrapper*, _object*, _object*, _object**, _object**, _object**) + 179
    12  sip.so                          0x0000000105403262 sipSimpleWrapper_init + 197
    13  org.python.python               0x0000000100075f55 type_call + 245
    14  org.python.python               0x000000010000c742 PyObject_Call + 98
    15  org.python.python               0x00000001000c0430 PyEval_EvalFrameEx + 12368
    16  org.python.python               0x00000001000c4786 PyEval_EvalCodeEx + 2118
    17  org.python.python               0x00000001000c2bc0 PyEval_EvalFrameEx + 22496
    18  org.python.python               0x00000001000c4786 PyEval_EvalCodeEx + 2118
    19  org.python.python               0x00000001000c2bc0 PyEval_EvalFrameEx + 22496
    20  org.python.python               0x00000001000c4786 PyEval_EvalCodeEx + 2118
    21  org.python.python               0x00000001000c2bc0 PyEval_EvalFrameEx + 22496
    22  org.python.python               0x00000001000c4786 PyEval_EvalCodeEx + 2118
    23  org.python.python               0x00000001000c48a6 PyEval_EvalCode + 54
    24  org.python.python               0x00000001000e912e PyRun_FileExFlags + 174
    25  org.python.python               0x00000001000e93ca PyRun_SimpleFileExFlags + 458
    26  org.python.python               0x000000010010044d Py_Main + 3101
    27  org.python.python               0x0000000100000f14 0x100000000 + 3860
  
    Thread 1:: Dispatch queue: com.apple.libdispatch-manager
    0   libsystem_kernel.dylib          0x00007fff8f7c0662 kevent64 + 10
    1   libdispatch.dylib               0x00007fff93213421 _dispatch_mgr_invoke + 239
    2   libdispatch.dylib               0x00007fff93213136 _dispatch_mgr_thread + 52
  
    Thread 2:
    0   libsystem_kernel.dylib          0x00007fff8f7bfe6a __workq_kernreturn + 10
    1   libsystem_pthread.dylib         0x00007fff89c2af08 _pthread_wqthread + 330
    2   libsystem_pthread.dylib         0x00007fff89c2dfb9 start_wqthread + 13
  
    Thread 3:
    0   libsystem_kernel.dylib          0x00007fff8f7bfe6a __workq_kernreturn + 10
    1   libsystem_pthread.dylib         0x00007fff89c2af08 _pthread_wqthread + 330
    2   libsystem_pthread.dylib         0x00007fff89c2dfb9 start_wqthread + 13
  
    Thread 0 crashed with X86 Thread State (64-bit):
      rax: 0x0000000000000000  rbx: 0x00007fff77830310  rcx: 0x00007fff5fbfe578  rdx: 0x0000000000000000
      rdi: 0x0000000000000d07  rsi: 0x0000000000000006  rbp: 0x00007fff5fbfe5a0  rsp: 0x00007fff5fbfe578
       r8: 0x0000000000000040   r9: 0x00007fff5fbfe400  r10: 0x0000000008000000  r11: 0x0000000000000206
      r12: 0x00000001041696b8  r13: 0x0000000106d34b20  r14: 0x0000000000000006  r15: 0x0000000103540510
      rip: 0x00007fff8f7bf866  rfl: 0x0000000000000206  cr2: 0x0000000103edfc50
  
    Logical CPU:     0
    Error Code:      0x02000148
    Trap Number:     133
  </code></pre>
  
  <p>I have installed all my libraries (Qt5.5, PyQt4, SIP4.17, ete3) in /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/. The libraries have all been installed fine, except when an external library tries to find the plugin, it can't find it.</p>
  
  <p>I am new to Python and Qt libraries, so any help would be appreciated. </p>