Merge branch 'master' into docking ...

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

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

Viewports: Minor tweaks. (#2471)

Version 1.71 WIP + fixed minor typo

Version 1.70

Merge branch 'master' into docking ...

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

Window: Fixed SetNextWindowSizeConstraints() with non-rounded positions making windows drift. (#2067, #2530)

Misc: Made IMGUI_CHECKVERSION() macro also check for matching size of ImDrawIdx.

Selectable: With ImGuiSelectableFlags_AllowDoubleClick doesn't return true on the mouse button releas efollowing the double-click. Only first mouse release + second mouse down (double-click) returns true. Likewise for internal ButtonBehavior() with both _PressedOnClickRelease | _PressedOnDoubleClick. (#2503)

Merge branch 'master' into docking ...

# Conflicts:
#	examples/imgui_impl_dx10.cpp
#	examples/imgui_impl_dx11.cpp
#	examples/imgui_impl_dx12.cpp
#	examples/imgui_impl_dx9.cpp
#	examples/imgui_impl_opengl2.cpp
#	examples/imgui_impl_opengl3.cpp
#	examples/imgui_impl_vulkan.cpp
#	imgui.cpp

ImDrawCallback_ResetRenderState, Examples: Added support for reset render state callback. (#2037, #1639, #2452)

Obsoleted GetContentRegionAvailWidth(), use GetContentRegionAvail().x instead. Kept inline redirection function.

Merge branch 'master' into docking ...

# Conflicts:
#	examples/example_sdl_opengl2/main.cpp
#	examples/example_sdl_opengl3/main.cpp
#	examples/example_sdl_vulkan/main.cpp
#	examples/imgui_impl_sdl.cpp
#	examples/imgui_impl_sdl.h
#	imgui.cpp

Misc comments, internal renaming, added disable indentation option to Columns demo section.

Viewports: Avoid rendering/swapping secondary viewports that are minimized. (#1542, #2496)

Increased IMGUI_VERSION_NUM arbitrarily, help narrowing down reports that don't include a commit hash. Add comments.

Merge branch 'master' into docking ...

# Conflicts:
#	imgui.cpp
#	imgui.h

Added SetNextItemWidth() helper to avoid using PushItemWidth/PopItemWidth() for single items.

Added commentary about ContentRegion functions. Added internal GetContentRegionMaxScreen() to facilitate internal code at the moment.

Internals: Columns: Tweaks, renaming. Metrics: Show rectangles for child windows. ...

Renamed SameLine() first parameter.

Merge branch 'vulkan_fix_master' into vulkan_fix_docking

Misc: Added IM_MALLOC/IM_FREE macros mimicking IM_NEW/IM_DELETE so user doesn't need to revert to using the ImGui::MemAlloc()/MemFree() calls directly.

Misc: Added IM_MALLOC/IM_FREE macros mimicking IM_NEW/IM_DELETE so user doesn't need to revert to using the ImGui::MemAlloc()/MemFree() calls directly.

Vulkan, Viewports: ImGui_ImplVulkan_RenderDrawData and renderer back-end automatically manage ImGui_ImplVulkanH_WindowRenderBuffers for each viewports so user doesn't have to do it. (#2461, #2348, #2378, #2097)

Merge branch 'master' into docking ...

# Conflicts:
#	examples/imgui_impl_dx9.cpp
#	examples/imgui_impl_opengl3.cpp

Examples: OpenGL3: Minor tweaks, clarifications + not calling glBindBuffer more than necessary in the render loop.

Merge branch 'master' into docking ...

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

Docking: Separating SharedFlags vs LocalFlags in dock node so settings can be applied to individual nodes. Made _NoResize logic on single node applies as expected. (#2423, #2109)

Docking: Renamed ImGuiDockNodeFlags_PassthruDockspace to ImGuiDockNodeFlags_PassthruCentralNode. + Comments, shallow tweaks. (#2109)

Comments (#2441) + Freeglut fixes (#2430)