Fix compiler warnings on windows.

Ignore some warnings inside 3rd party code and fix a lot of conversion
warnings.

Change-Id: I909f2f31a4639015bf7dd028d2d435ff1d1167bc
Reviewed-by: Christian Kandeler <christian.kandeler@theqtcompany.com>
Reviewed-by: Eike Ziller <eike.ziller@qt.io>
Reviewed-by: Christian Stenger <christian.stenger@theqtcompany.com>
Reviewed-by: David Schulz <david.schulz@theqtcompany.com>

src/libs/glsl/glslparser.h

@@ -114,7 +114,7 @@ private:
     inline int consumeToken() {
         if (_index < int(_tokens.size()))
             return _index++;
-        return _tokens.size() - 1;
+        return static_cast<int>(_tokens.size()) - 1;
     }
     inline const Token &tokenAt(int index) const {
         if (index == 0)