Docstring edits.  waitFrameCapture returns the errorCode.

I added to the docstrings of each function including which DLL function is being called.  I set waitFrameCapture to return the errorCode instead of passing it to VimbaException.  For a hardware trigger this lets the user handle errorCode -12 where a timeout has been reached.  Not handling this error causes problems (in my code) with either frame.getBufferByteData or camera.revokeAllFrames.