QtSupport: Forward-declare some classes.

Change-Id: I7f0eb6c4ea8620c8405f6d13c554c0ec913edd63
Reviewed-by: Daniel Teske <daniel.teske@digia.com>

src/plugins/android/androidruncontrol.cpp

@@ -36,6 +36,8 @@
 
 #include <projectexplorer/projectexplorerconstants.h>
 
+#include <QIcon>
+
 using namespace ProjectExplorer;
 
 namespace Android {