Docking: Fixed crash with ImGuiDockNodeFlags_AutoHideTabBar flag. (#2423, #2109)

Merge branch 'master' into docking ...

# Conflicts:
#	docs/CHANGELOG.txt
#	examples/imgui_impl_opengl3.cpp
#	imgui.cpp
#	imgui_internal.h

InputText: Fixed selection background starts rendering one frame after the cursor movement when first transitioning from no-selection to has-selection. (Bug in 1.69) (#2436) [@Nazg-Gul]

InputText: Simplify read-only code path.

IsWindowHovered() made change which should have no effect in master but fix result of IsWindowHovered(ImGuiHoveredFlags_ChildWindows) over multiple viewport in docking branch. (#2432)

Mention Julia binding in README (#2446) ...

Thank you!

Docking: BeginDocked() doesn't need to rely on tab bar data (will allow removing tab bar).

Docking: Preserve existing docked nodes when setting the ImGuiDockNodeFlags_NoDockingInCentralNode flag. (#2423, #2109)

Comments, todo list, remove trailing spaces.

Viewports: Fixed being unable to refocus windows when ConfigViewportsNoTaskBarIcon + ConfigViewportsNoDecoration are enabled. (#2420, #1542) [@PathogenDavid] + comments.

GetMouseDragDelta(): also returns the delta on the mouse button released frame. Verify that mouse positions are valid otherwise returns zero. Removed obsolete comment. Tweaked demo. (#2419)

Examples: OpenGL: Added a dummy GL call + comments in ImGui_ImplOpenGL3_Init() to detect uninitialized GL function loaders early, and help users understand what they are missing. (#2421)

Version 1.70 WIP

Demo: Custom rendering: Minor sizing issue fix.

Merge branch 'master' into docking ...

# Conflicts:
#	docs/CHANGELOG.txt
#	examples/example_win32_directx10/main.cpp
#	examples/example_win32_directx11/main.cpp
#	examples/example_win32_directx12/main.cpp
#	examples/example_win32_directx9/main.cpp

Version 1.69, comments, typos

Viewport: DestroyPlatformWindow() skips calling user function if PlatformWindowCreated is set. + Clarified comment about implicit Debug viewport which may be hogging a viewport.

Fixed main viewport not being marked as created, which broke updating the IME input position for the main viewport. ...

This change also removes the logic scattered about that compensated for PlatformWindowCreated being wrong for the main viewport.

Internals: Fixed Navigation from reaching ImGuiItemFlags_Disabled items (#211) + Examples comments

TabBar: Reworked scrolling policy (when ImGuiTabBarFlags_FittingPolicyScroll is set) to teleport the view when aiming at a tab far away the visible section, and otherwise accelerate the scrolling speed to cap the scrolling time to 0.3 seconds.

TabBar: Fixed Tab tooltip code making drag and drop tooltip disappear during the frame where the drag payload activate a tab.

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)

Fixed Clang and PVS warnings.

InputText: Fixed c779fbb leading to display of the wrong buffer when resizing a buffer. (#2400, #2006, #1443, #1008).

Demo: InputText: Demonstrating use of ImGuiInputTextFlags_CallbackResize. (#2006, #1443, #1008).

Added GetGlyphRangesVietnamese() helper. (#2403)

Internal: Removed unused fields from ImGuiMenuColumns.

Docking: Fixed node merging altering window position incorrectly in a way that would make SizeContents incorrect for the next frame (making scrollbar flicker). (#2414, #2109)

Viewport: Popups and Tooltips viewports are correctly parented to the parent window's viewport. (#2409, #1542)