Fixed warnings + readme

Examples: OSX: Added clipboard support. Fixed ignore list for xcode cruft. Comments about broken keys. (#1873)

Examples: Allegro5: Added support for ImGuiConfigFlags_NoMouseCursorChange flag. Added clipboard support. Unindexing buffers ourselves as Allegro indexed drawing primitives are buggy in the DirectX9 back-end.

Internals: Added GetItemID(), GetFocusID() for consistency. Made GetActiveID() inline. Comments, fixed typos, demo tweaks.

Examples: OSX: Fixed obsolete enums. Fixed keyboard mapping. Added missing keyboard modifiers. (#1873)

Examples: FreeGLUT: Fixed mapping of Space key. (#801)

Comments, documentation

Examples: FreeGLUT: Added FreeGLUT bindings. Added FreeGLUT+OpenGL2 example. (#801)

Examples: Win32: Fixed handling of mouse wheel messages to support finer position messages (typically sent by track-pads). (#1874)

Examples: Comments to make ImGuiConfigFlags_NoMouseCursorChange more visible (#1027). + Allegro5: Added support for ImGuiConfigFlags_NoMouseCursorChange flag.

Examples: Added imgui_impl_osx.mm bindings (#1870, #281)

Fixed Travis path + various paths in comments/documentations

Examples: Renamed imgui_impl_sdl2.cpp to imgui_impl_sdl.cpp (#1870) + changelog bits

Examples: Renamed example folders. (#1870)

Big example binding refactor (manually imported from Viewport branch, stripped out of Viewport code). (#1870) ...

Read examples/README.txt for some details.
ImDrawData: Added DisplayPos, DisplaySize fields honored by all backends (not strictly necessary to honor just now, but doing it to be ahead)

Missing examples changelog bits and todo list

Examples: OpenGL3: Removed unnecessary backup/restore of GL_ELEMENT_ARRAY_BUFFER_BINDING since this is part of the VAO state. (#1836)

Examples: iOS: Fixed missing call to CreateContext() + various shallow coding style tweaks. (#1835)

Examples: Comments about GLSL version not being the same as GL context version. (#1828)

Examples: GLFW: Made it possible to Shutdown/Init the backend again (by reseting the time storage properly). Changelog. Added to Vulkan example. (#1827)

Examples: GLFW* Make subsequent window creation possible.

Examples: OpenGL3: Trying to make the call to glBindSampler optional to make the example code easier to use/share with different context version. (#1806)

TODO list update + Changelog and comments for #1803.

Fixed clipboard paste memory leak in SDL examples. (#1803)

Examples: DirectX9: Comments, updated changelog, notes about usage of imconfig.h (#1790, #1687)

add renderstate D3DRS_SHADEMODE for Dx9 impl ...

add backuping transform for Dx9 impl
(#1790, #1687)

Added IMGUI_CHECKVERSION() macro to compare version string and data structure sizes in order to catch issues with mismatching compilation unit settings. (#1695, #1769)

Examples: Allegro 5: Renamed bindings from imgui_impl_a5.cpp to imgui_impl_allegro5.cpp.

Examples: Allegro 5: Added support for 32-bit indices setup via defining ImDrawIdx, to avoid an unecessary conversion (Allegro 5 doesn't support 16-bit indices).

Fix typos KeyDown => KeysDown