Examples: GLFW + OpenGL3: Initial attempt at implementing the viewport/platform api. (WIP/test API) (#1542)

Examples: DX11 + Win32: Initial attempt at implementing the viewport/platform api. (WIP/test API) (#1542)

Viewport: Initial viewport branch+ platform api commit (squashed from previous commits, still very WIP) (#1542)

Metrics: Added option to show begin order, useful for debugging.

Internal: Minor renaming.

Internals: Moving window: test mouse validity while translating window + using SetWindowPos().

Removed DisplayVisibleMin/DisplayVisibleMax facility (as part of # 1542). Misc comments.

Clearing next window data at the end of Begin() more reliably. Misc comments.

Internals: Settings: Added ReadCloseFn to allow handlers to sanitize data on a per-entry basis.

Examples: Misc tweaks/fixes.

Merge branch 'master' into examples_refactor ...

# Conflicts:
#	examples/opengl3_example/imgui_impl_glfw_gl3.cpp
#	examples/sdl_opengl3_example/imgui_impl_sdl_gl3.cpp

README.md typo fix

ImRect: Removed misleading IsFinite() function used by some Nav code.

Compacted some old Breaking Changes notes (Pre July 2015 stuff)

Changelog: Added all change infos since 1.53 up to the current version.

Changelog: Added Changelog with info from 1.48 to 1.53. Haven't added 1.53..current yet.

TreeNode: Renamed Beta ImGuiTreeNodeFlags_NavCloseFromChild to ImGuiTreeNodeFlags_NavLeftJumpsBackHere. (#1079)

ImDrawList: Better looking non-AA rectangle (lower-right corner and rounding). (#1646)

Examples: Fix d749d49 missing the deletion code. (#1217)

Examples: OpenGL3: Create the VAO in the render function so the setup can more easily be used with multiple shared GL context. (#1217)

stb_truetype: Fixed unused variable warnings for configuration where asserts are disabled. (#1642)

Examples: DirectX12: Merged to new example format, imgui_impl_dx12.cpp contains the DX12 stuff, couple with imgui_impl_win32.cpp

Merge branch 'master' into examples_refactor

ImDrawList: PushTextureID(): Removed unnecessary param by reference.

Examples: DirectX12: Tweaked assertion to more accurately represent what it wants to say. (#301)

Merge branch 'podgorskiy-master'

Merge branch 'master' of https://github.com/podgorskiy/imgui into podgorskiy-master

Update README.txt

Examples: DirectX12: Fixed shutdown issue. (#301)

Examples: DirectX12: Merge, various styling tweaks, update for 1.60 wip, synchronized Win32 features with other examples. (#301)