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

Changelog formatting update, Todo, comments. Tweak Child demo. Shuffle some code in NavUpdate().

Nav: When entering into a NavFlattened child we only consider the visible items for scoring (note that this only work assuming the NavFlattened child window has interactive items). Fixes accidentally hoping into a NavFlattened child. (#767)

Nav: NavFlattened: Fixed navigation miscrolling parent window when the current window is scrolling enough to keep the item in view. Fix feature added in e11610d6, typically affect large navigation steps (used by PageUp/PageDown). + comments (#787)

Internals: Added BeginDragDropTooltip() internal function to convey semantic (drag and drop tooltip doesn't get clipped within display boundaries). Revert part of 3218666. (#1739, #143).

Added ImGuiDragDropFlags_AcceptNoPreviewTooltip flag to disable drag source tooltip from the target site (#143)

Internals: Selectable: Renamed variables. Todo update.

Missing examples changelog bits and todo list

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

Added float GetWindowDpiScale(). (#1542, #1676)

ImVector: added erase(it first, it last) helper. Added erase_unsorted(it) helper. + todo fixes/additions

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

Comments + Internals: Selectable: decoupled internal flags and removed their menu / menu-item semantic as upcoming changes are requiring more flexibility.

Merge branch 'master' into viewport ...

# Conflicts:
#	imgui.cpp

Version 1.61 + todo additions

Merge branch 'master' into viewport ...

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

Merge branch 'data_types' ...

# Conflicts:
#	CHANGELOG.txt
#	imgui.cpp

TODO list update + Changelog and comments for #1803.

Moved DragScalar, InputScalar, SliderScalar to imgui.h as well as ImGuiDataType (#320, #643, #708, #1011)

Merge branch 'master' into viewport ...

# Conflicts:
#	examples/imgui_impl_dx9.cpp
#	imgui.cpp
#	imgui.h

Settings: Added LoadIniSettingsFromDisk(), LoadIniSettingsFromMemory(), SaveIniSettingsToDisk(), SaveIniSettingsToMemory(), io.WantSaveIniSettings. (#923, #993)

DragInt: Patch old format strings to replace %f by %d when using the DragInt() entry point. (#320, #643, #708, #1011)

Viewport, Platform: Refresh monitor list (win32, glfw) + avoid calling GetWindowFocus before platform window creation to not require of backend to null-check things inconsistently. (#1542)

Viewport: Removed unnecessary fields (now that the coordinate system is consistent accross viewports): MouseRefPrevViewport, MouseClickedPosViewportId. (#1542)

Viewport, Platform: Using Platform_GetWindowFocus to provide a much stronger heuristic of platform z-order, in replacement for when the back-end cannot provide io.MouseHoveredViewport. The pressure for it to work well increased with the use of viewports by popups/menus. (#1542)

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

Platform: Clarifying some comments in back-ends.

Viewport, Platform: Fixed IME positioning for multi-viewport. Moved API from ImGuiIO to ImGuiPlatformIO. Because it is extremely unlikely to people redefined this API manually the moving-forward-breakage is ok. (#1542) ...

SDL2 ime support under Win32 never worked properly because of SDL interferences.

Viewport: Clamp windows within monitors + fallback rescue window when it is out of sight (e.g. removed monitor, changed resolution) + Win32: declare primary monitor at the beginning of the list. (#1542)

Viewports: Todos, Tooltips/menus not automatically forced into their own viewport when the NoMerge flag is set (however the multiplication of viewports makes them more likely to protude and create their own). Win32: try to make primary monitor the first tin the list. (#1542)

Documentation bits. Misc comments.