title: Send keys with pywinauto doesn't work completely
body: <p>I want to send keys to a background program, but the sending doesn't work on all parts of my program (it has no child windows). The following code partially works.</p>
  <pre><code>from pywinauto import Application
  
  appWavie = Application(backend='win32').connect(handle=790164)
  Wavie = appWavie['Wavie']
  Wavie.send_keystrokes('123')
  </code></pre>
  <p>Is it possible to use the code provided by @lucasg in <a href="https://stackoverflow.com/a/13615802/19522915">Keyboard event with ctypes</a> as a <code>pywinauto</code> method?</p>
  <p>I would like to add <code>PressKey</code> and <code>ReleaseKey</code> methods to <code>pywinauto</code>. My code would look like this:</p>
  <pre><code>from pywinauto import Application
  
  appWavie = Application(backend='win32').connect(handle=790164)
  Wavie = appWavie['Wavie']
  
  VK_1 = 0x31
  
  Wavie.PressKey(VK_1)
  Wavie.ReleaseKey(VK_1)
  </code></pre>
  <p>I want to use these methods because they work in my program where <code>send_keystrokes</code> doesn't work, but <code>PressKey</code> and <code>ReleaseKey</code> don't work in the background.</p>