Viewport: Coupling non-main viewport to one window. Viewport name derived from the window. Added ImGuiConfigFlags_PlatformNoTaskBar, off by default (aka re-established task-bars by default for now). (#1542)

Viewport: Disable extra viewports from hosting other windows. (#1542)

Viewport: Reorganized viewport enable flags. Both user + platform + renderer need to enable a flag. (#1542)

Examples: Updated Makefile and batch files to work with new examples. Using lowercase "gl.h" as it seems this is what Linux wants.

Examples: Vulkan: Further refactor.

Examples: Vulkan: Moved CreateOrResizeWindowData func to imgui_impl_vulkan.h

Examples: Vulkan: Moved main.cpp data structures to imgui_impl_vulkan.h as shared helpers for the benefit of both the example and the platform/viewport renderer interface.

Viewport: Replaced UpdatePlatformWindows/RenderPlatformWindows by RenderAdditionalViewports(). The update is always called in EndFrame(). (#1542)

Examples: Vulkan: Moved variables into per-window data, refactored/tweaks to that the bug functions main.cpp for both SDL and GLFW examples match (they'll probably be moved to imgui_impl_vulkan as helpers).

Examples: Vulkan: Fix 7b968b0

Examples: Vulkan: Reduced duplicate code by skipping present on the first frame. Amend 201d589 by @ParticlePeter

Examples: Vulkan: Various tweak. Misc refactor into per-frame data. Duplicate buffer creation code moved to CreateOrResizeBuffer().

Examples: GLFW, Vulkan: GLFW binding viewport tweaks to supports Vulkan better (do not call SwapBuffer, share context etc.). Added DUMMY (empty) platform/viewport interface in the viewport code.

Examples: Renamed glfw error callback so it's more clear what it is.

Merge branch 'examples_refactor' into viewport ...

# Conflicts:
#	examples/directx10_example/main.cpp
#	examples/directx11_example/main.cpp
#	examples/directx12_example/main.cpp
#	examples/opengl3_example/main.cpp
#	examples/sdl_opengl2_example/main.cpp
#	examples/sdl_opengl3_example/main.cpp
#	examples/sdl_vulkan_example/main.cpp
#	examples/vulkan_example/main.cpp
#	imgui.h

Examples: Vulkan: SDL: Fixed missing resize handler (not properly merged from #1367) + tweaks.

Examples: Vulkan: Moved code into shared helpers: ImGui_ImplVulkan_SelectSurfaceFormat, ImGui_ImplVulkan_SelectPresentMode.

Examples: Vulkan: Various tweaks to name variable more consistently like Vulkan + a few comments + a few imgui style code compaction.

Examples: Vulkan: Debug report tweak + always enable in Debug build.

Examples: Fixed enabling IMGUI_VULKAN_DEBUG_REPORT which was broken during refactor because of duplicate 'extensions' local variable.

Renamed ImGuiNavFlags io.NavFlags to ImGuiConfigFlags io.ConfigFlags. (#787)

Renamed ImGuiNavFlags io.NavFlags to ImGuiConfigFlags io.ConfigFlags. (#787)

Examples: NULL pointers for consistency.

Examples: Vulkan: Formatting and tweaks (to match SDL's main).

Examples: Vulkan: Fixed GLFW calls.

Examples: Vulkan: Extracted into imgui_impl_vulkan.*, reused imgui_impl_glfw* files.

Examples: Vulkan: Fix for empty draw data (init time) + fixed warning.

Examples: Vulkan: Added .vcproj files.

Obsoleted the io.RenderDrawListsFn callback, you can call your graphics engine render function after ImGui::Render(). Use ImGui::GetDrawData() to retrieve the ImDrawData* to display..(#1599) ...

Examples: Updated examples.

Examples: Added Changelog to make updates easier.