Merge branch 'master' into docking ...

# Conflicts:
#	docs/CHANGELOG.txt
#	imgui.cpp
#	imgui.h

Removed redirecting functions/enums that were obsoleted in version 1.51 (June 2017): ImGuiCol_Column*, ImGuiSetCond_*, IsItemHoveredRect(), IsPosHoveringAnyWindow(), IsMouseHoveringAnyWindow(), IsMouseHoveringWindow(), IMGUI_ONCE_UPON_A_FRAME.

Version 1.72 WIP

Docking: Fixed rendering of outer decoration happening on non-visible docked window (#2623, #2109). Revealed by 0770449. We are actually better than before now, as previously those would get unnecessarily get rendered into a hidden draw list.

Merge branch 'master' into docking ...

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

Version 1.71 + comments

Internals: Reworked RenderTextEllipsis() to satisfy what we need for table headers.

Readme, comments, dear imgui prefixes

Log/Capture: Fixed BeginTabItem() label not being included in a text log/capture. ...

Extracted tab rendering code into a RenderTextEllipsis() function.

Window: child windows outer decorations (e.g. scrollbar) are rendered as part of their parent window, avoiding the creation of an extraneous draw command. ...

+ Metrics: inverted color of clip rect vs vertices bounding box when hovering a draw command, so the color matches the per-vertex preview.

Internals: Added drawlist and color arg to RenderArrow(), RenderBullet(). Reordered args for RenderPixelEllipsis.

Made PushID() behave the same in 32-bit and 64-bit, by not padding the integer into a void*. (Also technically faster.)

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.

Synced/merged minor cruft from docking branch to minimize drift. AFAIK the only meaningful no-op change is that the call UpdateHoveredWindowAndCaptureFlags() was moved above UpdateMouseMovingNewFrame() to match what docking branch has been doing for a while.

Revert "Changed syntax for (very rarely used) IMGUI_OVERRIDE_DRAWVERT_STRUCT_LAYOUT mechanism, instead you only need to '#define ImDrawVert MyDrawVert' to use this feature, avoiding the need to declare the entire structure within an awkward macro. Using the old macro will now error with a message pointing you to the new method. (#38, #103, #1172, #1231, #2489)" ...

This reverts commit 597c024.

Changed syntax for (very rarely used) IMGUI_OVERRIDE_DRAWVERT_STRUCT_LAYOUT mechanism, instead you only need to '#define ImDrawVert MyDrawVert' to use this feature, avoiding the need to declare the entire structure within an awkward macro. Using the old macro will now error with a message pointing you to the new method. (#38, #103, #1172, #1231, #2489)

Merge branch 'master' into docking ...

# Conflicts:
#	imgui.cpp
#	imgui_internal.h

Window: Fixed one case where auto-resize by double-clicking the resize grip would make either scrollbar appear for a single frame after the resize. Moved Scrollbar visibility block.

Internals: Moved scrollbar visibility calculation block below the call to UpdateManualResize(). This commit is _intended_ to have no side-effect (next commit will). Also moved ItemWidthDefault calculation below rectangles.

Scrollbar overlap an extra WindowBorderSize amount on the left to make all distances consistent. Reverted to BorderSize not affecting work/contents rectangles. Scrollbar, Style: Changed default style.ScrollbarSize from 16 to 14.

Internals: Minor no-op tidying up toward solving the WindowPadding / WindowBorderSize / ScrollbarSize overlapping mess. ...

+ Demo: Use SetScrollY().

Fixed newly created window (e.g. appearing child window) from having scrollbar active on the first frame. (fix 6e03b27) + reworded code a little. (+1 squashed commits) ...

Fixed auto-resize with AlwaysVerticalScrollbar or AlwaysHorizontalScrollbar flags not taking account of the expect scrollbar sizes.

Internals: Storing ScrollMax into a member. Mostly to facilitate debugging. Also locking down window->Scroll slightly lower in the Begin function.

TextWrapped, PushTextWrapPos(0.0f) within a window with horizontal scrolling from not covering the full horizontal area (previously only worked with an explicit contents size).

Internals: Renamed SizeContents to ContentSize, SizeContentsExplicit to ContentSizeExplicit. Tweaked Metrics->Show Rectangles functionality.

Window rectangles: Changed WorkRect to cover the whole region including scrolling (toward obsolete ContentsRegionRect) + using full WindowPadding*1 padding. ...

Tweaked InnerClipRect.
TreeNode, CollapsingHeader: Fixed highlight frame not covering horizontal area fully when using horizontal scrolling. (#2211, #2579)
TabBar: Fixed BeginTabBar() within a window with horizontal scrolling from creating a feedback loop with the horizontal contents size.
Columns: Fixed Columns() within a window with horizontal scrolling from not covering the full horizontal area (previously only worked with an explicit contents size). (#125)
Demo: Added demo code to test contentsrect/workrect

Clarified behavior of SetNextWindowContentSize(). Content size is defined as the size available after removal of WindowPadding on each sides. So SetNextWindowContentSize(ImVec2(100,100)) + auto-resize will always allow submitting a 100x100 item without creating a scrollbar, regarding of WindowPadding.The exact meaning of ContentSize for decorated windows was previously ill-defined.

Window rectangles: Made InnerRect not affected by window border sizes. its few users shouldn't be meaningfully affected.

Merge branch 'master' into docking

Comments (#2599). Moved branch Changelog above 1.71 wip one. Added some missing changelog bits.