title: App crashing because of glGetString
body: <p>I am running cocos2d-iphone 1.0.0 and following <a href="http://www.tinytimgames.com/2011/07/22/cocos2d-and-arc/" rel="nofollow" title="this">this</a> tutorial to use cocos2d with ARC.  Unfortunately, I am getting a 'SIGABRT' crash error whenever I try to add a TMX Tiled Map to a CCLayer.  I have traced this problem down to the <code>-(BOOL)checkForGLExtension:(NSString *)searchName</code>, and even further to within this function to <code>NSString *extensionsString = [NSString stringWithCString:glExtensions encoding: NSASCIIStringEncoding];</code></p>
  
  <p>Here is the checkForGLExtension function: </p>
  
  <pre><code>- (BOOL) checkForGLExtension:(NSString *)searchName {
  // For best results, extensionsNames should be stored in your renderer so that it does not
  // need to be recreated on each invocation.
  NSLog(@"%@", glExtensions);
  NSString *extensionsString = [NSString stringWithCString:glExtensions encoding: NSASCIIStringEncoding];
  NSLog(@"%@", extensionsString);
  NSArray *extensionsNames = [extensionsString componentsSeparatedByString:@" "]; }
  </code></pre>
  
  <p>The <code>encoding:</code> part of <code>NSString *extensionsString = [NSString stringWithCString:glExtensions encoding: NSASCIIStringEncoding];</code>is probably making the application crash.  I am also receiving NULL in my logs for <code>GL_VENDOR</code>, <code>GL_VERSION</code>, <code>GL_RENDERER</code>, and even <code>glExtensions</code>.</p>
  
  <p>Looking back at gl.h in the OpenGLES.framework shows me this: </p>
  
  <pre><code>/* StringName */
  #define GL_VENDOR                         0x1F00
  #define GL_RENDERER                       0x1F01
  #define GL_VERSION                        0x1F02
  #define GL_EXTENSIONS                     0x1F03
  </code></pre>
  
  <p>In which all of them are NULL.</p>