Fixed warnings + readme

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

Fixed merge.

Merge branch 'master' into viewport ...

# Conflicts:
#	examples/imgui_impl_opengl2.cpp
#	examples/imgui_impl_opengl2.h
#	examples/imgui_impl_opengl3.cpp
#	examples/imgui_impl_opengl3.h
#	imgui.cpp
#	imgui.h

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.

Examples: Fixed example vcproj names in Viewport branch.

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

Merge branch 'master' into viewport ...

# Conflicts:
#	examples/imgui_impl_dx10.cpp
#	examples/imgui_impl_dx10.h
#	examples/imgui_impl_dx11.cpp
#	examples/imgui_impl_glfw.cpp
#	examples/imgui_impl_glfw.h
#	examples/imgui_impl_opengl2.cpp
#	examples/imgui_impl_opengl2.h
#	examples/imgui_impl_opengl3.cpp
#	examples/imgui_impl_sdl.cpp
#	examples/imgui_impl_sdl.h
#	examples/imgui_impl_vulkan.h
#	examples/imgui_impl_win32.cpp

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

Merge branch 'master' into viewport ...

# Conflicts:
#	examples/imgui_impl_sdl.cpp

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

Examples: Renamed example folders. (#1870)

Merge branch 'examples_refactor2' into viewport (#1870) ...

# Conflicts:
#	examples/README.txt
#	examples/directx11_example/main.cpp
#	examples/directx12_example/main.cpp
#	examples/imgui_impl_dx10.cpp
#	examples/imgui_impl_dx11.cpp
#	examples/imgui_impl_dx12.cpp
#	examples/imgui_impl_glfw.cpp
#	examples/imgui_impl_opengl2.cpp
#	examples/imgui_impl_opengl2.h
#	examples/imgui_impl_opengl3.cpp
#	examples/imgui_impl_sdl2.cpp
#	examples/imgui_impl_sdl2.h
#	examples/imgui_impl_vulkan.cpp
#	examples/imgui_impl_vulkan.h
#	examples/imgui_impl_win32.cpp
#	examples/imgui_impl_win32.h
#	examples/opengl2_example/main.cpp
#	examples/opengl3_example/main.cpp
#	examples/sdl_opengl2_example/main.cpp
#	examples/sdl_opengl3_example/main.cpp
#	examples/sdl_vulkan_example/main.cpp
#	examples/vulkan_example/main.cpp
#	imgui.cpp
#	imgui.h

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)

Examples: Documentation

Examples: Fixed Makefile, batch files.

Examples, Platform: Removed the call to ImGui::NewFrame() from the platform _NewFrame() function e.g. ImGui_ImplWin32_NewFrame(), ImGui_ImplSDL2_NewFrame(), ImGui_ImplGlfw_NewFrame(), etc. Moved to main.cpp for consistency. (#1542)

Examples: Added .. folder in include path to remove the awkward #include "../imgui_impl_xxx.h" statements.

Missing examples changelog bits and todo list

Merge branch 'master' into viewport ...

# Conflicts:
#	examples/opengl2_example/imgui_impl_glfw_gl2.cpp
#	examples/opengl3_example/imgui_impl_glfw_gl3.cpp
#	examples/sdl_opengl3_example/imgui_impl_sdl_gl3.cpp
#	examples/sdl_opengl3_example/imgui_impl_sdl_gl3.h
#	examples/vulkan_example/imgui_impl_glfw_vulkan.cpp

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)