Examples: Refactored opengl3_exapmle into a glfw specific file that can be copied and pasted

Examples: DirectX examples uses WM_KEYDOWN/WM_KEYUP ...

Fixes pressing Enter in IME being caught by application right after
validating an IME input.

Windows: setup a default handler for ImeSetInputScreenPosFn so IME (Japanese/Chinese) inputs are positioned correctly. ...

User need to set io.ImeWindowHandle

Replaced dependency on glew (inc. prebuilt one for Windows) by gl3w in source form ...

Expecting something to break now.

Renamed ImGuiSetCondition_*** to ImGuiSetCond_*** and ImGuiCondition_FirstUseThisSession to ImGuiCond_Once

Calculate frame-rate for the user, as a purely luxurious feature ...

..and to reduce sample code size a little.

Minor formatting tweaks, comments

Examples: changed default background color.

Examples: more comments on loading fonts.

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

OpenGL3 example: fix growing of VBO

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

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

OpenGL example: allow resizing window.

OpenGL3 example: fixed mouse handling.

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

OpenGL3 example: unregistered mouse callback for mouse click-release faster than frame interval.

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