Addendum to #2635. Add support for multi-viewports in SDL+DX!! example. making all Win32-centric back-ends handle PlatformHandleRaw. Using the field to use/store the HWND for internal purpose in SDL/GLFW back-ends. (#1542)

Synced/merged minor cruft from master branch to minimize drift. Only meaningful change AFAIK is removing ImGuiComboFlags_PopupAlignLeft flag from the tab list combo emitted by TabBar.

Merge branch 'master' into docking ...

# Conflicts:
#	examples/imgui_impl_glfw.cpp
#	examples/imgui_impl_win32.cpp
#	imgui.cpp
#	imgui_internal.h

Platform Binding for GLFW updated with the release of GLFW 3.3 (#2547) ...

* With the release of GLFW 3.3, it is now possible to detect correctly monitors working area (see GLFW_HAS_MONITOR_WORK_AREA). GLFW 3.3 also introduced the window hint GLFW_FOCUS_ON_SHOW. This fixed the case where a new created window (viewport) takes the focus even if not visible.

* Disable a GLFW 3.2 windows hack when GLFW 3.3 is detected (related to window focused when shown).

IO: changed AddInputCharacter(unsigned short c) signature to AddInputCharacter(unsigned int c). ...

Examples/Backends: Don't filter characters under 0x10000 before calling io.AddInputCharacter(), the filtering is done in io.AddInputCharacter() itself. This is in prevision for fuller Unicode support. (#2538, #2541)

Merge branch 'master' into docking ...

# Conflicts:
#	examples/example_sdl_opengl2/main.cpp
#	examples/example_sdl_opengl3/main.cpp
#	examples/example_sdl_vulkan/main.cpp
#	examples/imgui_impl_sdl.cpp
#	examples/imgui_impl_sdl.h
#	imgui.cpp

Examples: SDL: Gamepad support minor amend. Fixes ImGuiBackendFlags_HasGamepad not being set. Enable in Emscripten demo. Tweaks. (#2509, #2484).

Merge branch 'master' into docking ...

# Conflicts:
#	examples/imgui_impl_glfw.cpp
#	examples/imgui_impl_sdl.cpp

Examples: GLFW, SDL: Preserve DisplayFramebufferScale when main viewport is minimized. (This is particularly useful for the viewport branch because we are not supporting per-viewport frame-buffer scale. It fixes windows not refreshing when main viewport is minimized.) (#2416)

Examples + Viewport: GLFW: context wasn't set when using multiple windows. (#2392)

Comments for Linux/Mac (#2117)

Merge branch 'master' into docking ...

# Conflicts:
#	imgui.cpp
#	imgui.h

Examples: Extracted gamepad code into ImGui_ImplGlfw_UpdateGamepads(). Renamed matching Win32 function for consistency. ...

Added more link to nothing's oversample document. Spacing bits.

Merge branch 'master' into viewport ...

# Conflicts:
#	examples/example_sdl_vulkan/main.cpp
#	examples/imgui_impl_dx11.cpp
#	examples/imgui_impl_dx12.cpp
#	examples/imgui_impl_glfw.cpp
#	examples/imgui_impl_sdl.cpp
#	examples/imgui_impl_vulkan.h
#	imgui.cpp

Removed trailing spaces (#2038, #2299)

Merge branch 'master' into viewport ...

# Conflicts:
#	docs/CHANGELOG.txt
#	examples/imgui_impl_win32.cpp
#	examples/imgui_impl_win32.h

Examples: Win32: Added support for XInput games (if ImGuiConfigFlags_NavEnableGamepad is enabled).

Merge branch 'master' into viewport ...

# Conflicts:
#	examples/imgui_impl_sdl.cpp

Examples: Comments about GLFW/SDL versions

Tweaked asserts

Viewport: Win32, GLFW, SDL: Clarified back-ends by using global mouse position direction. GLFW: disabled io.MouseHoveredViewport setting under Mac/Linux. (#1542, #2117) + various comments.

About, IO: Added io.BackendPlatformName, io.BackendRendererName for informational/QA purpose.

Merge branch 'master' into viewport ...

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

About, IO: Added io.BackendPlatformName, io.BackendRendererName for informational/QA purpose.

Viewport: Added support for minimized window which caused problem when ImGuiBackendFlags_HasMouseHoveredViewport was not supported. (#1542) + todo

Viewport: Avoid unnecessary reapplying platform pos/size every frame. (#2205) + Fix GLFW ImGui_ImplGlfw_CreateWindow() from not applying position immediately. Clear LastNameHash properly (bug already fixed in Docking branch)

Merge branch 'master' into viewport + specific changes for GLFW callbacks ...

# Conflicts:
#	examples/example_glfw_opengl3/main.cpp
#	examples/example_win32_directx11/main.cpp
#	examples/example_win32_directx9/main.cpp
#	examples/imgui_impl_glfw.cpp

Examples: GLFW: User previously installed GLFW callbacks are now saved and chain-called by the default callbacks. (#1759)

Examples: Misc comments mainly related to GLFW callbacks. (#1759)

Merge branch 'master' into viewport