Merge branch 'master' into viewport ...

# Conflicts:
#	examples/sdl_opengl2_example/main.cpp
#	examples/sdl_opengl3_example/main.cpp
#	examples/vulkan_example/main.cpp

Examples: Renamed applications to emphasis on use of GLFW as a platform framework + minor local tweaks

Examples: Using draw_data->DisplaySize, followup to c50198d. Fix Vulkan secondary viewport rendering. SDL+Vulkan: Matched changes. Fix vcprojs. (#1542, #1042)

Examples: Updated Makefile and batch files to work with new examples. Using lowercase "gl.h" as it seems this is what Linux wants.

Examples: Added Makefile for SDL+OpenGL2 example. (#1668)

Examples: Added Makefile for SDL+OpenGL2 example. (#1668)

Renamed ImGuiStyleVar_Count_ to ImGuiStyleVar_COUNT for consistency with other enums. Added

Renamed ImGuiNavFlags io.NavFlags to ImGuiConfigFlags io.ConfigFlags. (#787)

Renamed ImGuiNavFlags io.NavFlags to ImGuiConfigFlags io.ConfigFlags. (#787)

Examples: SDL: Initial attempt at implementing the viewport/platform api. (WIP/test API) (#1542) ...

ImGui_ImplSDL2_Init() now takes a SDL GL context.

Merge branch 'master' into examples_refactor

Examples: SDL: Using %SDL2_DIR% in the .vcproj instead of %SDL_DIR%, the earlier is more standard.

Examples: Using SDL2_DIR instead of SDL_DIR (more standard).

Examples: OpenGL: Cast call to glPolygonMode(). (#1628).

Examples: Mouse cursor handling comments/tweaks to homogenize. (#1495)

Examples: SDL: Extracted into imgui_impl_sdl.*, reused imgui_impl_opengl* files.

Examples: SDL: Added .vcproj files.

Examples: SDL: Minor stylistic tweaks. Fixed handling of ImGuiMouseCursor_None so it doesn't underflow array. Fixed harmless uninitialized pointer. (#1626)

Renamed misleading ImGuiMouseCursor_Move to ImGuiMouseCursor_ResizeAll. SDL: Fixed cursor. (#1626)

Use SDL system cursors in SDL examples. (#1626) ...

(Squashed 4 commits)

Obsoleted the io.RenderDrawListsFn callback, you can call your graphics engine render function after ImGui::Render(). Use ImGui::GetDrawData() to retrieve the ImDrawData* to display..(#1599) ...

Examples: Updated examples.

Examples: Added Changelog to make updates easier.

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: Examples: Added commented out io.NavFlags |= ImGuiNavFlags_EnableKeyboard to all examples. (#787)

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

Merge branch 'master' into context

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.