Viewport: Made it possible for the moving window to detach and recreate its own Viewport (used by Docking)

Internals: HoveredWindowUnderMovingWindow special handling for drag and drop of window without altering the _NoInputs window flag, which worked but messed up the IsWindowHovered() user-facing flags.

Viewport: Reapply/recover ownership of viewport which is convenient for docking but also can recover from faulty .ini files. (#1542)

Internals: Misc/shallow merge from Docking branch.

Nav: Added a CTRL+TAB window list and changed the highlight system accordingly. (#787)

Merge branch 'master' into viewport ...

# Conflicts:
#	imgui.cpp

Internals: Removed RootWindowForTabbing, won't be needed. Nav: Not starting NavWindowingTarget when a modal is active (was not noticeable).

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

Demo: Added basic Drag and Drop demo. (#143, #1931)

Drag and Drop: Calling BeginTooltip() between a BeginDragSource()/EndDragSource() or BeginDropTarget()/EndDropTarget() uses adjusted tooltip settings matching the one created when calling BeginDragSource() without the ImGuiDragDropFlags_SourceNoPreviewTooltip flag. (#143) + additional safety checks.

Internals: Moved selectable flags to avoid collision with public flags + rewrote some tests so we can consistently grep for (held && hovered)

Drag and Drop: Fixed ImGuiDragDropFlags_SourceNoDisableHover to affect hovering state prior to calling IsItemHovered() + fixed description. (#143)

Fix missing ImmReleaseContext in default Win32 IME handler (#1932)

Generalized d11d211e so regular popups (without the AlwaysAutoResize flag) also have a smaller minimum size, but reduced it to an arbitrary 4.0f instead of 1.0f to ease debugging of faulty situations. (#1909)

Merge branch 'master' into viewport ...

# Conflicts:
#	imgui.cpp

Drag and Drop: Fixed an incorrect assert when dropping a source that is submitted after the target (bug introduced with 1.62 changes related to the addition of IsItemDeactivated()). (#1875, #143)

Examples: Comments + shallow coding convention tweak to be consistent across examples and with imgui_impl_osx

Examples: Removed old example_apple/ + tweak comments (#1873)

Merge branch 'warrenm_osx'

Apple: Fixed example_osx_opengl2, renamed to example_apple_opengl2 + misc comments

Allow popup from ignoring the style.WindowMinSize values so short menus are not padded. (#1909) Wider generalization of b166037.

Internals: Removed unused ShadeVertsLinearAlphaGradientForLeftToRightText code.

Removed per-window ImGuiWindowFlags_ResizeFromAnySide beta flag in favor `io.OptResizeWindowsFromEdges=true` to enable the feature globally. (#1495) The feature is not currently enabled by default because it is not satisfying enough.

Introduced a new Metal renderer implementation and a new example illustrating usage of Metal on macOS and iOS (partially addresses #1873)

Internals: BeginChildEx tweaks.

Examples: Comments, bits of documentation

OSX: Various tweaks to imgui_impl_osx courtesy of @warrenm + fix NewFrame position which has been moved recently master. (#1873)

Merge branch 'master' into osx ...

# Conflicts:
#	examples/.gitignore
#	examples/README.txt

Links and thanks. Comments on using BeginCombo/EndCombo + moved the Combo() implementations closer to each others to maximize user seeing how it is implemented from any of the secondary function body.

Ignore list: added emscripten output