Renamed FontAtlas to Fonts. Further cleanup/comments.

ImFontAtlas allows loading multiple fonts into same texture. Revamped new init API for 1.30

Removed PixelCenterOffset, uncesssary

Merge remote-tracking branch 'upstream/master' into 2015-01-truetype ...

Conflicts:
	imgui.cpp
	imgui.h

Examples: Added a color slider for the background color + tweak first example use of button.s

ImFont::GetTextureData API allow to retrieve 8/32 bits data + lazily load defaults font ...

Examples: OpenGL3 and DirectX11 back to using 32-bits texture solely for
ease of integration.

Mde it optional to new() io.Font - however it stills needs to be loaded.

Examples' Says "OpenGL2" vs "OpenGL3" in title bar.

TAB to spaces

Speculative fix for warnings for GCC/Clang

Examples: all supports TextureID in renderer, added LoadFontTexture() function.

Loading TTF file with stb_truetype. Broke setup API slightly. Font baked, packed with space for custom data. Embeds compressed ProggyClean.

Examples: Fixed warnings for Clang

Examples: Added STB_IMAGE_STATIC in examples to avoid conflicting implementation. Relate to #109

New and better Set[Next]Window(Pos|Size|Collapsed) API. ...

Removed rarely useful SetNewWindowDefaultPos() in favor of new API.

OpenGL example: allow resizing window.

Fix Clang warning with offsetof() macro? Added -Wall in OpenGL 3 example.

Examples: DirectX11: moved shader to be close to its usage location,

Examples: OpenGL3: cleaned up to match features of OpenGL2 example

Examples: adding title to the top of each examples. Cleaning up file headers.

Example apps: accumulate mouse wheel to accodomate for slow framerate.

DirectX11 example: further tweaks/massaging (-15 lines). Syncing example.

Removed Microsoft IME handler in examples, too confusing. Moved to imgui.cpp instruction block.

Tab->Spaces :(

Added DirectX11 example application (code is too long!)

Example code: warning fix + comments.

Updated example code.

Moved IO.Font*** options to inside the IO.Font-> structure.. Added IO.FontGlobalScale setting (vs Font->Scale)

Renamed ImBitmapFont -> ImFont, removed abstraction-pretend typedef

Fixed compatibility with std::vector if user decide to #define ImVector