Examples: SDL: Added Changelog at the top of the imgui_impl files. (#1618)

Merge branch 'context' ...

# Conflicts:
#	examples/allegro5_example/main.cpp
#	examples/directx10_example/main.cpp
#	examples/directx11_example/main.cpp
#	examples/directx9_example/main.cpp
#	examples/marmalade_example/main.cpp
#	examples/opengl2_example/main.cpp
#	examples/opengl3_example/main.cpp
#	examples/sdl_opengl2_example/main.cpp
#	examples/sdl_opengl3_example/main.cpp
#	examples/vulkan_example/main.cpp

Nav: Keyboard is now automatically mapped based on io.KeyDown[]. (#787)

Added ImGuiKey_Space, mapped in every examples. Will be required for navigation. (#787)

Merge branch 'master' into context

Examples: SDL+GL3: Added Navigation keyboard mapping. (#787)

Merge branch 'master' into navigation

Examples: SDL: Using SDL_GetPerformanceCounter() / SDL_GetPerformanceFrequency() to handle framerate over 1000 fps properly. Noticed bad inputs artefacts in Nav branch at 2000 fps without this. (#996)

Examples: SDL2: Enabling vsync. Using scancode consistently, fixed keyboard weirdness.

Examples: Organized header files to make available features more visible.

Merge branch 'master' into context

Moved extra_fonts/ to misc/fonts/. Moved .natvis file to misc/natvis/ (#1569)

Examples: Using Dark theme by default. (#707). Tweaked demo code.

Examples: Using #include "imgui.h" instead of <imgui.h> appear correct-er as per standard? xcode+clang are very nitpicky there.

Examples: Makefile leave CXX alone, instead leave commented out options. (nb: codeship doesn't seem have clang++)

Examples: Use Clang in old Makefile.

Examples: Synced Makefile comments. Added build/ folder into git ignore list/

Examples: Updated for reorganized context functions. Calling CreateContext(), DestroyContext() in example code. Removed Shutdown() from binding code. (#1565, #586, #992, #1007, #1558)

Examples: Simplified mouse wheel handling. (#1463)

Horizontal mouse wheel: renamed io.MouseHorizWheel to io.MouseWheelH. Reorganized the code in NewFrame(). Examples: Updated GLFW+GL and SDL+GL accordingly. (#1463)

Merge branch 'tseeker/20171127-feature-horiz-wheel' of https://github.com/tseeker/imgui into tseeker-tseeker/20171127-feature-horiz-wheel ...

# Conflicts:
#	examples/sdl_opengl2_example/imgui_impl_sdl_gl2.cpp
#	examples/sdl_opengl3_example/imgui_impl_sdl_gl3.cpp

Examples: SDL: Using SDL_CaptureMouse() to retrieve coordinates outside of client area when dragging. (#1559) ...

Digging into sdl window/mouse stuff will also be useful for multi-viewport work.

Examples: SDL: Minor renaming.

Examples: SDL: Using SDL_WINDOW_INPUT_FOCUS instead of SDL_WINDOW_MOUSE_FOCUS (which is ~~hovered). We should use SDL_CaptureMouse + SDL_WINDOW_MOUSE_CAPTURE_FLAG which requires SDL 2.0.4 will give it a try shortly. (#1559)

Examples: SDL: Fixed mapping of Insert key (#1555, fix bug introduced in #1541)

Added ImGuiKey_Insert for future use. Setup in all example bindings. (#1541)

Examples: OpenGL3+SDL: Changed GLSL shader version to 150 (#1466, #1504)

Examples: Using IM_OFFSETOF macro. + Comments

Examples: Comments about invalid mouse pos.

Examples: Comments, synched some minor drift between examples + stronger suggestion to use StyleColorsDark().