Allowing DeltaTime==0.0f to not assert

SDL example: tweaks and fixes.

Merge branch 'SampleSDL2' of https://github.com/CedricGuillemet/imgui into CedricGuillemet-SampleSDL2

Examples: OpenGL3: simplified code. Upload each vertex array separately. (cf #264)

Update ios example for API changes and index rendering

Merge remote-tracking branch 'origin' into 2015-03-antialiased-primitives

Fixed clang/gcc warnings (#133)

Merge branch 'ios_example_merge'

iOS Example: Optimise PNG files size

iOS example: shallow tweaks and fixes (untested)

iOS example working based on modified OpenGL3 example + Synergy

AA branch: undo d35c1a9, thickness is back but goes through non-AA path (#133)

AA branch: more comments on breaking changes (#133)

AA branch: Agressively renamed all fields of ImDrawList, ImDrawCmd, ImDrawData to match the rest of our coding convention (#133)

AA branch: removed the 'thickness' parameter from ImDrawList::AddLine()

AA branch: API breaking change documentation

Merge remote-tracking branch 'origin' into 2015-03-antialiased-primitives

Columns/ImDrawList: dispatch render of each column in a sub-draw list and merge on closure, saving draw calls (#125)

ImDrawList: winodw draw lists destructed properly on Shutdown()

Fixed ListBoxHeader() not honoring negative sizes the same way as BeginChild() or BeginChildFrame() (#263)

More debug-build friendly ImVector<> use micro optimisations for the most bottle-neck bunchs

AA branch: further use of ImVector<> Data/Size

Merge remote-tracking branch 'origin' into 2015-03-antialiased-primitives ...

Conflicts:
	imgui.cpp

ImVector<> access to Size/Capacity/Data (#262)

Merge remote-tracking branch 'origin' into 2015-03-antialiased-primitives ...

Conflicts:
	examples/directx11_example/imgui_impl_dx11.cpp
	examples/directx9_example/imgui_impl_dx9.cpp
	examples/opengl3_example/imgui_impl_glfw_gl3.cpp
	examples/opengl_example/imgui_impl_glfw.cpp
	imgui.cpp

Removed the majority of size_t from the code. ImVector<> now uses int. (#262) ...

May trigger new compilation warnings?

Fixed minor zealous Clang warning (demo code intentionally uses strdup() to be copiable)

ImVector<> cannot be re-defined (#262)

Metrics window: "Show clipping rectangles when hovering ImDrawList" enabled by default

ImRect (internal) fixed ImVec4 constructor, argh (broken e7e2fcd)