Merge branch 'viewport' into docking ...

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

Merge branch 'master' into viewport ...

# Conflicts:
#	examples/example_sdl_vulkan/main.cpp
#	examples/imgui_impl_dx11.cpp
#	examples/imgui_impl_dx12.cpp
#	examples/imgui_impl_glfw.cpp
#	examples/imgui_impl_sdl.cpp
#	examples/imgui_impl_vulkan.h
#	imgui.cpp

Removed trailing spaces (#2038, #2299)

Merge branch 'master' into viewport ...

# Conflicts:
#	examples/imgui_impl_win32.cpp

Examples: Win32: Using wc.lpszClassName instead of duplicating the literal. + tweak README format.

Fix merge in Docking branch, remove ConfigDockingWithShift flag from DX11 example + misnamed function.

Merge branch 'viewport' into docking ...

# Conflicts:
#	examples/example_allegro5/main.cpp
#	examples/example_win32_directx9/main.cpp

Merge branch 'master' into viewport + added style tweak block when viewports are enabled ...

# Conflicts:
#	examples/example_glfw_opengl3/main.cpp
#	examples/example_sdl_opengl3/main.cpp
#	examples/example_win32_directx11/main.cpp

Examples: Setting up style before bindings, so in complex binding (vulkan/dx12) it isn't miles away from the context creation.

Merge branch 'viewport' into docking ...

# Conflicts:
#	examples/example_allegro5/main.cpp
#	examples/example_marmalade/main.cpp

Merge branch 'master' into viewport + specific changes for GLFW callbacks ...

# Conflicts:
#	examples/example_glfw_opengl3/main.cpp
#	examples/example_win32_directx11/main.cpp
#	examples/example_win32_directx9/main.cpp
#	examples/imgui_impl_glfw.cpp

Examples: Misc comments mainly related to GLFW callbacks. (#1759)

Merge branch 'viewport' into docking ...

# Conflicts:
#	examples/example_glfw_opengl2/main.cpp
#	examples/example_glfw_opengl3/main.cpp
#	examples/example_glfw_vulkan/main.cpp
#	examples/example_sdl_opengl2/main.cpp
#	examples/example_sdl_opengl3/main.cpp
#	examples/example_sdl_vulkan/main.cpp
#	examples/example_win32_directx10/main.cpp
#	examples/example_win32_directx11/main.cpp
#	examples/example_win32_directx12/main.cpp
#	examples/example_win32_directx9/main.cpp

Viewport: Enabled viewports by default in more example apps.

Merge branch 'viewport' into docking ...

# Conflicts:
#	docs/CHANGELOG.txt
#	imgui_demo.cpp
#	imgui_internal.h

Examples: Using "dear imgui" terminology in all examples headers/comments + fix minor typo.

Examples: Enabled Docking + Nav by default in the branch. (#351)

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

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: Renamed example folders. (#1870)