Internals: Exposed NavScoreItemGetQuadrant() as ImGetDirQuadrantFromDelta() in imgui_internal.h

Added non-const ImVec2 [] operator for consistency (and because some docking code needs it.)

Merge branch 'master' into viewport ...

# Conflicts:
#	examples/imgui_impl_sdl.cpp
#	imgui.cpp

Made it possible to move a window by dragging from the Collapse button (past the drag threshold). Extracted some code out to a CollapseButton() function.

Internals: Renamed one of the arrow functions so their name don't collide.

Examples: Using fully qualified "Dear ImGui" name in window titles.

Fixed horizontal mouse wheel not forwarding the request to the parent window if ImGuiWindowFlags_NoScrollWithMouse is set. (#1463, #1380, #1502)

Internals: Extracted part of NewFrame() into a UpdateMouseWheel() function.

Added asserts to catch illegal modifications of the font atlas between NewFrame() and EndFrame()/Render(). (#1958)

Changed ImGui::GetTime() return value from float to double to avoid accumulating floating point imprecisions over time.

Readme: fixed typo + patron

Ignore GCC warning (-Wclass-memaccess) in imgui.h (#1959)

Tweaked Contributing guidelines, Issue and PR templates

Viewport: Fixed a situation when the implicit Debug window can hold on a zombie viewport which platform window is not properly destroyed. (#1542)

ImGuiTextFilter, TextRange: removed cruft from TextRange since it's not a publicly and generic helper at the moment + marked internal stuff + changed a reference to a pointer. (#1879)

Examples: SDL: Removed SDL_HAS_WARP_MOUSE_GLOBAL in the non-viewport branch. (#1954) (+1 squashed commits)

Merge branch 'master' into viewport ...

# Conflicts:
#	imgui.cpp

Nav: Fixed CTRL+TAB windowing list from always showing the implicit Debug window. (#787)

Fix warning when IMGUI_DEFINE_MATH_OPERATORS is already defined by build system. (#1950)

Viewport: Removed the need for the back-end to fill io.MousePosViewport, it seems unnecessary at this point. (#1542)

Internals: Viewport: Renamed g.MouseRefViewport to g.MouseViewport. (#1542)

Viewport: when moving window we use the moving window viewport unless drag and dropping. This is to fix e.g. IsItemHovered() + Tooltip pattern that may be active while moving a window. (#1542)

Viewport: Revert part of 7abf72e, the viewport ownership stealing is problematic. (#1542). Will rework in the context of docking. (+1 squashed commits) ...

+ Fixed unused prototype warning (left-over from a merge)

Demo: Clarified the use of IsItemHovered()/IsItemActive() right after being in the "Active, Focused, Hovered & Focused Tests" section. This will be of more importance with the introduction of tabs.

Merge branch 'master' into viewport ...

# Conflicts:
#	examples/imgui_impl_dx10.cpp
#	examples/imgui_impl_dx11.cpp
#	imgui_demo.cpp

Demo: Fixed spacing from b629f90 change.

Examples: Tweaked the main.cpp example structure for all examples. (There are a few hidden agendas here: 1) I would like to avoid encouraging people from using the implicit "Debug" window, and promote using Begin/End. In spite of my best attempt, there are a few feature of the upcoming docking system that cannot work 100% properly for the implicit Debug window, so future proof let's not put that feature in the spotlight too much for new users. 2) Moved dumb hardcoded positions into a single spot that can be replaced with a viewport relative position and not affect other demo windows. 3) Calling ShowDemoWindow before anything else, also for the benefit of a specific docking demo which will have an ordering constraint which is not really problematic in a real app but shouldn't be put forward in the demo.

Examples: DX10, DX11: Fixed unreleased resources in Init and Shutdown functions. (#1944)

Demo: Spacing.

Merge branch 'master' into viewport ...

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