Simplified ImDrawList system (samples are 20 lines shorter) + merged title bar draw bar.
OpenGL example now use the fixed function-pipeline. Code down by 120 lines.
Update README.md
Fixed columns lines not being pixel aligned
Fix for gcc type qualifier warnings.

With -Wall -Wextra -Werror, it is not possible to compile against
imgui.h due to const correctness violation in ImVector.
Merge pull request #14 from Roflraging/constiteratorfix

Fix for gcc type qualifier warnings.
Added InputFloat2(), SliderFloat2()