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

Viewport: Fixed PushClipRectFullScreen() missing out on negative coordinates. Among other things, the outer highlight during CTRL+Tab wouldn't appear in negative coordinates monitors. (~#2176, #1542)

Tabs to Spaces, comments.

Merge branch 'master' into docking ...

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

InputText: Work-around for buggy standard libraries where isprint('\t') returns true. (#2467, #1336) ...

Not using isprint. + todo items.

Docking: Fixed focus restore lagging by a frame when a tab stops being submitted. (#2109) Building on a little build of technical debt there, should transition toward a more general docking-agnostic system (#2304)

Viewport: Renamed member + added note about a Docking issue with restoring focus.

Docking: Remove code in BeginDocked() to set HiddenFramesCannotSkipItems based on upcoming tab bar selection, solely based on focus (might break something subtle?). Follow-up to c355ed1. (#2453, #2109)

Docking: Disable SkipItems when directly/programmatically focused (possible generalization of code currently in BeginDocked which relies on tab bar interaction, will remove that code in next commit). (#2453, #2109)

Merge branch 'master' into docking ...

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

Internals: Renamed the ImGuiWindow HiddenFrameXXX fields to decorrelate them from resizing behavior, as those values are set by other logic.

Docking: Added ImGuiDockNodeFlags_NoTabBar (not exposed publicly). (#2423, #2109)

Docking: Internals: Moved CentralNode and HiddenTabBar state into LocalFlags for consistency. (#2423, #2109)

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: Fix DockBuilderAddNode() not storing flags when creating floating node.

Renamed ImGuiDockNodeFlags_Dockspace to ImGuiDockNodeFlags_DockSpace for consistency. DockBuilderCopyDockspace() to DockBuilderCopyDockSpace(). Made casing consistent elsewhere. (#2109)

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

Docking: Tweak and silencing PVS studio static analyzer (back to zero warnings among our selected ones).

Docking: Fixed an issue where windows docked into a node that's part of their dockspace wouldn't recover their order correctly after init. (#2109) ...

(It only worked on floating dock node for the accidental reason that BeginDocked would generally early out on the first frame)

Docking: Wrapping tab bar creation/destroy to make it easier to debug them.

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

Rearrange code in UpdateMouseWheel(). (#2424, #1463) + Fix old io.FontAllowUserScaling feature (probably should be made obsolete, but until then best fixed)

Implement horizontal scrolling with Shift+Scroll ...

This is standard scrolling behaviour in most applications.

Merge branch 'master' into docking ...

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

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

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.