Merge branch 'master' into navigation ...

# Conflicts:
#	imgui.cpp

Examples: Using Dark theme by default. (#707). Tweaked demo code.

Examples: Tweaks formatting.

Merge branch 'master' into navigation

Examples: Using #include "imgui.h" instead of <imgui.h> appear correct-er as per standard? xcode+clang are very nitpicky there.

Nav: Examples: DirectX11, Glfw+GL3: Basic code to map keyboard inputs when io.NavFlags & ImGuiNavFlags_EnableKeyboard is set. (will iterate/tweak before spreading to other examples). (#787)

Examples: Updated for reorganized context functions. Calling CreateContext(), DestroyContext() in example code. Removed Shutdown() from binding code. (#1565, #586, #992, #1007, #1558)

Examples: DirectX10,DirectX11: Moved call to OMSetRenderTargets() in main loop so example code can integrate more nicely with other code.

Examples: Comments, synched some minor drift between examples + stronger suggestion to use StyleColorsDark().

Renamed the emblematic ShowTestWindow() function to ShowDemoWindow(). Kept redirection function (will obsolete).

Examples: Added a bunch of comments/referencs related to io.WantCaptureMouse, io.WantCaptureKeyboard (#1262, #1237, #1219, #635, #1058, #1051, #912, #533, #703, #446, #459, #364, #213, #52, and more)

Examples: Added more comments near the fonts loading section, to catch common questions and errors (e.g. #1397, #1366, #1341, #1222, #1193, #1115, #951, etc.)

Examples: DirectX9/10/11: Renamed WndProc handler to use a generic Win32 name + returning 0 to all messages is more correct.

Examples: Adding Roboto to the commented-out font list, and removing the unnecessary ProggyClean from there.

Examples: Avoid using ImColor() to not tempt newcomers into looking at it

Examples: DirectX11: allow creating device with feature level 10 sinec we don't really need much for that example. (#1333)

Examples: Main: Removed call to SetNextWindowSize()

Renamed ImGuiSetCond_XXX type and enums to ImGuiCond_XXX, kept old enums under #ifdef IMGUI_DISABLE_OBSOLETE_FUNCTIONS

Examples: Enable vsync by default in example applications (#1213, #1151)

Examples; DirectX10/11: Added comments about removing dependency on d3dcompiler DLL (#638)

Examples: DirectX10, DirectX11: Removed seemingly unnecessary bunch of rasterizer state creation code.

Trim trailing spaces

Examples: DX11: Remove debug flag (#415)

Examples: Header comments.

Examples: Clarified comments. Removed font merging example from comments.

Examples: DirectX9/11: Removed assumption about Unicode build in example main.cpp (#399)

Examples: update all examples with same comment (#389)

Fonts: added Cousine-Regular.ttf

Examples: comments.

Examples: Simplified font examples comments.