Fixups for OSX

Add makefile for freeglut

Examples: Vulkan: Added shader sources/references in the .cpp source.

Merge branch 'master' into docking ...

# Conflicts:
#	examples/imgui_impl_dx9.cpp
#	examples/imgui_impl_opengl3.cpp

InputText, Examples/SDL: Emulate \t input if back-end doesn't provide it. (#1336, #2467) ...

+ Fix some output filename in SDL build batch files.

Examples: Vulkan: Using IM_ARRAYSIZE() where possible.

Examples: Vulkan: Added missing support for 32-bit indices (#define ImDrawIdx unsigned int). + demo typo

Examples: DirectX9: Fixed erroneous assert in ImGui_ImplDX9_InvalidateDeviceObjects(). FreeType: Fixed suggested code to not require an initial build call.. (#2454)

Examples: DirectX12: Various tidying up.

Examples: OpenGL3: Minor tweaks, clarifications + not calling glBindBuffer more than necessary in the render loop.

Merge branch 'master' into docking ...

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

Comments (#2441) + Freeglut fixes (#2430)

Merge branch 'master' into docking ...

# Conflicts:
#	docs/CHANGELOG.txt
#	examples/imgui_impl_opengl3.cpp
#	imgui.cpp
#	imgui_internal.h

Comments, todo list, remove trailing spaces.

Examples: OpenGL: Added a dummy GL call + comments in ImGui_ImplOpenGL3_Init() to detect uninitialized GL function loaders early, and help users understand what they are missing. (#2421)

Version 1.70 WIP

Merge branch 'master' into docking ...

# Conflicts:
#	docs/CHANGELOG.txt
#	examples/example_win32_directx10/main.cpp
#	examples/example_win32_directx11/main.cpp
#	examples/example_win32_directx12/main.cpp
#	examples/example_win32_directx9/main.cpp

Version 1.69, comments, typos

Internals: Fixed Navigation from reaching ImGuiItemFlags_Disabled items (#211) + Examples comments

Merge branch 'master' into docking ...

# Conflicts:
#	examples/imgui_impl_glfw.cpp
#	examples/imgui_impl_sdl.cpp

Examples: GLFW, SDL: Preserve DisplayFramebufferScale when main viewport is minimized. (This is particularly useful for the viewport branch because we are not supporting per-viewport frame-buffer scale. It fixes windows not refreshing when main viewport is minimized.) (#2416)

Merge branch 'master' into docking ...

# Conflicts:
#	examples/example_win32_directx11/main.cpp
#	examples/example_win32_directx12/main.cpp
#	examples/example_win32_directx9/main.cpp
#	imgui.cpp

Examples: Win32+DirectX: moved helper functions below main.

Viewports: Renamed ConfigViewportsNoParent to ConfigViewportsNoDefaultParent. Fix outdated comments in examples.

Fix typos. (#2413)

Examples: DirectX9: Added support for multi-viewport (#2394)

Merge branch 'master' into docking ...

# Conflicts:
#	imgui_demo.cpp

Examples: DirectX9: Minor changes to match the other DirectX examples more closely. (#2394)

Merge branch 'master' into docking ...

# Conflicts:
#	examples/imgui_impl_opengl3.cpp

Examples: OpenGL: Fix to be able to run on ES 2.0 / WebGL 1.0. [@rmitton, @gabrielcuvillier]