Remove all trailing spaces

No real changes, just clean up sources by removing trailing spaces from
all the non-generated files.

This should hopefully avoid future commits mixing significant changes
with insignificant whitespace ones.

src/qt/timer.cpp

@@ -28,7 +28,7 @@ bool wxQtTimerImpl::Start( int millisecs, bool oneShot )
         return false;
 
     m_timerId = startTimer( GetInterval() );
-    
+
     return m_timerId >= 0;
 }