Merge branch 'master' into navigation

Nav: Comments, added enum to clarify NavForward code. (#787)

Nav: Mouse hovering selectable / menu items only activate them if they are on the active NavLayer. (#787)

Nav: Debug overlay uses default font. (#787)

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

Examples: Makefile leave CXX alone, instead leave commented out options. (nb: codeship doesn't seem have clang++)

Examples: Use Clang in old Makefile.

Examples: Synced Makefile comments. Added build/ folder into git ignore list/

Examples: Apple: Fixed filenames in OSX xcode project.

Examples: Vulkan: FIxed warnings in 32-bit modes (vulkan uses VkDeviceSize which is always 64-bit long)

Added IMGUI_USER_CONFIG to define a custom configuration filename. (#255, #1573, #1144, #41)

imconfig.h comments

ImVector comment (#1577)

Merge branch 'master' into navigation

Scrollbar: Fix for ScrollbarY enable check after ScrollbarX has been enabled. (#1574) Looks like a bug introduced in c36e586.

Scrollbar: Fix ScrollbarX enable test subtracting WindowPadding.x. This has been here since 65a191c (#246) tho at the time it is possible that SizeContents wasn't calculated as evenly. ...

Test: auto-resize with: ImGui::Begin("Test", NULL, ImGuiWindowFlags_HorizontalScrollbar); ImGui::Button("##xxx", ImVec2(500,500)); ImGui::End();

Nav: Drag, Slider: When already past a limit and pushing in the direction of the limit, we don't clamp values again. (#787)

Nav: Cleaning up + using ImGuiInputSource source enum instead of a silly bool. (#787)

Nav: Added keyboard moving and resizing via the CTRL-TAB windowing mode. (#787)

Fixed potential warning (forward declaration and definition didn't match signature. forward declaration only here for consistency)

Nav: Keyboard: Added CTRL+TAB (and CTRL+Shift+TAB) style window selection. (#787)

Nav: Style: Improved display of windowing highlight (for focus selection via PadMenu or Ctrl+TAB). (#787, #707)

Nav: Examples: Glfw+GL3: Added basic gamepad mapping code when io.NavFlags & ImGuiNavFlags_EnableGamepad is set. (will iterate/tweak before spreading to other examples). (#787)

Nav: Fixed renaming of c09016b that were incorrect. ImGuiNavInput_PadLeft -> PadDpadLeft, _PadScrollLeft -> PadLStickLeft. (#787)

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)

Fix SetNextWindowContentSize() with 0.0f on Y axis (or SetNextWindowContentWidth()) overwriting the contents size. Broken in eab6333. (#1363)

Internals: ImRect::Contains(ImRect&) include boundaries (whereas Contains(ImVec2) should not).

Merge pull request #1572 from rainbru/build-examples-fix ...

Fix building instruction in a couple of README

Fix allegro5_example build instructions

Fix sdl_opengl2_example filename in README.md's build instructions