[GuiLib] Prefix ++/-- operators should be preferred for non-primitive types.
[GuiLib] Technically the member function 'Foo::bar' can be static.
[GuiLib]  Possible inefficient checking for 'foo' emptiness.
[GuiLib]  Variable 'foo' is reassigned a value before the old one has been used.
[JpegIO] Common realloc mistake: 'm_inputBuff' nulled but not freed upon failure.
[GuiLib] Technically the member function 'Foo::bar' can be const.
[DirectXGraphics] Checking if unsigned variable 'foo' is less than zero.
[GuiLib] The scope of the variable 'foo' can be reduced.
[GuiLib] 'Foo::operator=' should return 'Foo &'.
[GuiLib] Member initialization issues, i.e.:
         - Member variable 'Foo::bar' is not initialized in the constructor.
         - Member variable 'Foo::bar' is in the wrong place in the initializer list.
         - Variable 'foo' is assigned in constructor body.
           Consider performing initialization in initialization list.
[Guilib] Make class 'Foo' non-copyable.
[GUIWindow] Consecutive return, break, continue, goto or throw statements are unnecessary.
[GraphicContext] Variable 'newRes' is assigned a value that is never used.
[GUICallback] Correct operators &operator=(GUIEvent<Cookie> &aEvent) and &operator=(Callback<Result, Cookie> &aCallback).
Merge pull request #3113 from ace20022/cleanup_guilib

[guilib] Cleanup things found by Cppcheck