Merge branch 'master' into docking ...

# Conflicts:
#	examples/imgui_impl_dx10.cpp
#	examples/imgui_impl_dx10.h
#	examples/imgui_impl_dx11.cpp
#	examples/imgui_impl_dx11.h
#	examples/imgui_impl_dx9.cpp
#	examples/imgui_impl_dx9.h
#	examples/imgui_impl_opengl3.cpp
#	examples/imgui_impl_opengl3.h
#	examples/imgui_impl_osx.h
#	examples/imgui_impl_osx.mm
#	imgui.cpp
#	imgui.h
#	imgui_demo.cpp
#	imgui_internal.h

ImDrawList: Store initial flags for the frame in ImDrawListSharedData, reducing code duplication in setting up the flags.

CollapsingHeader: When a close button is enabled, better clip the label to avoid overlap. (#600)

Internal: Renamed InnerMainRect to InnerVisibleRect. Printing coordinates in Metrics window.

Docking: Saving local _NoResize flag. (#2583)

Docking: Saving the NoTabBar, NoWindowMenuButton, NoCloseButton fields of dock node into the .ini file. Added them to the Metrics window. (#2583, #2423, #2109).

Comments, todo entries, moved ImGuiSelectableFlagsPrivate in higher ranges to match others.

Docking: Clarified terminology of docking/tablist/collapse button into Window Menu button matching master. Added private ImGuiDockNodeFlags_NoWindowMenuButton, ImGuiDockNodeFlags_NoCloseButton flags. (#2583, #2109)

Merge branch 'master' into docking ...

# Conflicts:
#	imgui.cpp
#	imgui_internal.h
#	imgui_widgets.cpp

Internal: CloseButton takes an upper-left corner + a size to be consistent with similar widgets.

Internals: Extracted some of the tab bar shrinking code into a ShrinkWidths() function so columns/table can use it.

Merge branch 'master' into docking ...

# Conflicts:
#	imgui.cpp
#	imgui_internal.h

Internals: Added InnerWorkRect equal to old InnerClipRect, added InnerWorkRectClipped actually clipped.

Fix OuterRectClipped not being clipped correctly, which resulted in child window outside visible bound to not be marked with SkipItems. Broken in b50c61c. ...

+ Comments on InnerClipRect being misleading. Demo: Tweak to sizing of child window in the Layout->Scrolling section.

Merge branch 'master' into docking ...

# Conflicts:
#	imgui.cpp

Fixed GCC mem-access warnings (#2565) ...

+ using "if defined" more consistently for Clang.

Merge branch 'master' into docking ...

# Conflicts:
#	examples/imgui_impl_glfw.cpp
#	examples/imgui_impl_win32.cpp
#	imgui.cpp
#	imgui_internal.h

Fixed uses of IsItemDeactivated(), IsItemDeactivatedAfterEdit() on multi-components widgets and after EndGroup(). (#2550, #1875)

Internal: Renamed fields + minor tweaks (probably shallow break stack-layout pr, sorry!)

Internal: Removed GetNextItemWidth(), relying on ItemAdd or NextItemData.ClearFlags() to clear the width data. Amend 5078fa20 and undo some of its effects of imgui_widgets.cpp

Renamed SetNextTreeNodeOpen() to SetNextItemOpen(). Refactored SetNextItemXXX stuff to match SetNextWindowXXX code closely.

Internal: Storing flags for NextWindowData so that we can clear everything with a single write and remove dummy condition fields.

Internal: Minor tidying/reordering of sections within ImGuiContext / window DC.

Merge branch 'master' into docking ...

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

Internal: Scrollbar: Extracted scrollbar code for other uses (eg. table v2 scrolling without using a child window).

Internals: Columns: Renamed fields. Comments and tweak. Moved a demo block.

Internal: Refactored Separator into SeparatorEx(), exposed ImGuiSeparatorFlags_SpanAllColumns in imgui_internal.h and support without. (#759) + misc comments

Columns: Fixed Separator from creating an extraneous draw command. Fixed Selectable with SpanAllColumns flag from creating an extraneous draw command. (#125)

Viewports: Minor tweaks. (#2471)

Version 1.71 WIP + fixed minor typo