Merge branch 'master' into viewport ...

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

imgui_impl_opengl3: Comments. (#1987)

Examples: imgui_impl_opengl3.cpp Using #ifdef GL_SAMPLER_BINDING instead of if (glBindSampler) (#1985)

Examples: OpenGL3: Tweaks, added changelog. (#1941)

Examples; imgui_impl_opengl3.cpp to work with Emscripten (#1941) ...

* Add some ifdefs to add emscripten specific params and includes

* Update imgui_impl_opengl3.cpp

* Update imgui_impl_opengl3.cpp

* Update imgui_impl_opengl3.cpp

* replace __EMSCRIPTEN_BUILD__ with __EMSCRIPTEN__

* replace GLFW_INCLUDE_ES3 with direct header

* removing useless glfw include

* Making call to glPolygonMode() optional

Merge branch 'master' into viewport ...

# Conflicts:
#	examples/imgui_impl_opengl3.cpp
#	imgui.cpp
#	imgui.h
#	imgui_draw.cpp
#	imgui_internal.h

Examples: include for intptr_t on tdm-gcc + mingw32 (#1936) + mouse buttons comments

Examples: OpenGL3: Added shaders more versions of GLSL + made the example app default to GL 3.0 + GLSL 130 (instead of GL 3.2 + GLSL 150) unless on Mac. (#1938, #1900, #1513, #1466, etc.)

OpenGL3: Added error output when shaders fail to compile / link. (#1938)

Merge branch 'master' into viewport ...

# Conflicts:
#	imgui.cpp

Examples: Comments, Demo: Log early out, TODO. (#1553)

Merge branch 'master' into viewport ...

# Conflicts:
#	imgui.cpp

Examples: Comments, bits of documentation

Merge branch 'master' into viewport ...

# Conflicts:
#	imgui.cpp

Examples: OpenGL3: Remove misleading or unnecessary "#version 150" strings.

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

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

Comments, documentation

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

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)

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

Merge branch 'master' into viewport ...

# Conflicts:
#	examples/opengl3_example/imgui_impl_glfw_gl3.cpp
#	examples/sdl_opengl3_example/imgui_impl_sdl_gl3.cpp
#	imgui.cpp
#	imgui.h

Viewport: Fixed mouse hover flicker on mouse button release frame after moving a window. (#1542) ...

Platform: Clarifying some comments in back-ends.

Viewports, DPI: Renamed config flags. (#1542)

Merge branch 'master' into viewport ...

# Conflicts:
#	examples/imgui_impl_dx10.cpp
#	examples/imgui_impl_dx11.cpp
#	examples/imgui_impl_dx12.cpp
#	examples/imgui_impl_dx9.cpp
#	examples/opengl2_example/imgui_impl_glfw_gl2.cpp
#	examples/opengl3_example/imgui_impl_glfw_gl3.cpp
#	examples/sdl_opengl2_example/imgui_impl_sdl_gl2.cpp
#	examples/sdl_opengl3_example/imgui_impl_sdl_gl3.cpp
#	examples/vulkan_example/imgui_impl_glfw_vulkan.cpp
#	imgui.h

Viewport, Platform: Added void* to render/swap buffer functions. Comments. (#1542, #1042)

Viewport, Examples: Renamed types used by examples. (#1542)

Viewport, Platform: Refactored platform interface. Removed need to use imgui_internal.h in backends. Split viewport into public facing ImGuiViewport and internal structure. Exposing enough data to provide custom tweaked renderers. Renamed handlers, fixed lots of inconsistencies. (#1542, #1042)