Merge branch 'master' into viewport (inc Vulkan resize fix merge #1042)

Misc comments, todos + reintroduced removed ImGuiCol defines under !IMGUI_DISABLE_OBSOLETE_FUNCTIONS wrap.

Style: CloseButton() now display a proper cross. Using Button colors for background. Removed ImGuiCol_CloseButton, ImGuiCol_CloseButtonActive, ImGuiCol_CloseButtonHovered as the closing cross uses regular button colors now. (#707)

Viewport, DPI: Some early work on per-viewport DPI support. At the moment the easiest way is to replace fonts during the ChangedViewport callback, but down the line we should aim at handling some of it at ImFont level. (#1542, #1676)

ImFont: Added FindGlyphNoFallback. Fixed MergeMode broken by 1ef1acb

Merge branch 'master' into viewport

Viewport,Platform: Added GetWindowDpiScale() platform interface, changes of scale are reflected by positioning and resizing windows in their given viewport. (#1542)

Viewport: Changed signature of ResizeViewport to be consistent with other similar functions.

Viewport: Coupling non-main viewport to one window. Viewport name derived from the window. Added ImGuiConfigFlags_PlatformNoTaskBar, off by default (aka re-established task-bars by default for now). (#1542)

Merge branch 'master' into font_offset

Font: Fixed MergeMode adding duplicate glyphs data instead of reusing existing (broken by 072d6d8)

Fonts: Fixed debug name not being zero-terminated if longer than storage buffer + made buffer slightly longer as well.

Comments, Changelog

Drag and Drop: Increased payload data type to 32 characters. (#143)

Viewport: Reorganized viewport enable flags. Both user + platform + renderer need to enable a flag. (#1542)

Merge branch 'master' into viewport ...

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

Viewport: Tracking current viewport we are appending to + added callback in PlatformInterface for DPI purpose (WIP). (#1542)

Comments, FAQ update.

Merge branch 'master' into viewport ...

# Conflicts:
#	examples/allegro5_example/main.cpp
#	examples/directx10_example/main.cpp
#	examples/directx11_example/main.cpp
#	examples/directx12_example/main.cpp
#	examples/directx9_example/main.cpp
#	examples/imgui_impl_dx10.cpp
#	examples/imgui_impl_dx11.cpp
#	examples/imgui_impl_dx12.cpp
#	examples/imgui_impl_dx9.cpp
#	examples/imgui_impl_glfw.h
#	examples/imgui_impl_vulkan.cpp
#	examples/opengl2_example/imgui_impl_glfw_gl2.cpp
#	examples/opengl2_example/main.cpp
#	examples/opengl3_example/imgui_impl_glfw_gl3.cpp
#	examples/opengl3_example/main.cpp
#	examples/sdl_opengl2_example/imgui_impl_sdl_gl2.cpp
#	examples/sdl_opengl2_example/main.cpp
#	examples/sdl_opengl3_example/imgui_impl_sdl_gl3.cpp
#	examples/sdl_opengl3_example/main.cpp
#	examples/vulkan_example/main.cpp
#	imgui.cpp
#	imgui.h

Renamed ImGuiStyleVar_Count_ to ImGuiStyleVar_COUNT for consistency with other enums. Added

Added ArrowButton(). Exposed ImGuiDir.

BeginCombo(): Added ImGuiComboFlags_NoArrowButton and ImGuiComboFlags_NoPreview flags + hover color matches drag and sliders.

Viewport: Replaced UpdatePlatformWindows/RenderPlatformWindows by RenderAdditionalViewports(). The update is always called in EndFrame(). (#1542)

Allow user to override ImTextureId. (#1641)

Nav: Added links to PNG/PSD files for PS4 and Switch. Fixed suggested Joy-con mapping as per typical Nintendo-style mapping. (#787)

Added ImGuiConfigFlags_IsSRGB, ImGuiConfigFlags_IsTouchScreen (strictly for user storage)

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

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

Viewport: Initial viewport branch+ platform api commit (squashed from previous commits, still very WIP) (#1542)

Removed DisplayVisibleMin/DisplayVisibleMax facility (as part of # 1542). Misc comments.