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]

Examples: OpenGL: Comments about versions and loaders. (#2393, #2351)

Merge branch 'master' into docking ...

# Conflicts:
#	docs/CHANGELOG.txt
#	examples/imgui_impl_opengl3.cpp
#	imgui_widgets.cpp

Examples: OpenGL: Fix for OSX not supporting OpenGL 4.5, we don't try to read GL_CLIP_ORIGIN even if the OpenGL headers/loader happens to define the value. (#2366, #2186)

Merge branch 'master' into docking ...

# Conflicts:
#	examples/imgui_impl_opengl2.cpp
#	examples/imgui_impl_opengl3.cpp
#	imgui.cpp
#	imgui_widgets.cpp

ImDrawData: Added FramebufferScale field (currently a copy of the value from io.DisplayFramebufferScale). ...

This is to allow render functions being written without pulling any data from ImGuiIO, allowing incoming multi-viewport feature to behave on Retina display and with multiple displays. If you are not using a custom binding, please update your render function code ahead of time, and use draw_data->FramebufferScale instead of io.DisplayFramebufferScale. (#2306, #1676)
Examples: Metal, OpenGL2, OpenGL3: Fixed offsetting of clipping rectangle with ImDrawData::DisplayPos != (0,0) when the display frame-buffer scale scale is not (1,1). While this doesn't make a difference when using master branch, this is effectively fixing support for multi-viewport with Mac Retina Displays on those examples. (#2306) Also using ImDrawData::FramebufferScale instead of io.DisplayFramebufferScale.
Examples: Clarified the use the ImDrawData::DisplayPos to offset clipping rectangles.

Merge branch 'master' into docking ...

# Conflicts:
#	imgui.cpp
#	imgui_demo.cpp

Minor tweaks to reduce false positive of PVS Studio static analyzer.

Merge branch 'master' into docking ...

# Conflicts:
#	examples/imgui_impl_opengl3.cpp
#	imgui.cpp
#	imgui.h

Examples: OpenGL3: Using GLSL 4.10 shaders for any GLSL version over 410 (e.g. 430, 450). (#2329) [@BrutPitt]

Merge branch 'master' into viewport ...

# Conflicts:
#	examples/example_sdl_vulkan/main.cpp
#	examples/imgui_impl_dx11.cpp
#	examples/imgui_impl_dx12.cpp
#	examples/imgui_impl_glfw.cpp
#	examples/imgui_impl_sdl.cpp
#	examples/imgui_impl_vulkan.h
#	imgui.cpp

Removed trailing spaces (#2038, #2299)

About, IO: Added io.BackendPlatformName, io.BackendRendererName for informational/QA purpose.

Merge branch 'master' into viewport ...

# Conflicts:
#	examples/imgui_impl_dx10.cpp
#	examples/imgui_impl_dx11.cpp
#	examples/imgui_impl_glfw.cpp
#	examples/imgui_impl_opengl2.cpp
#	examples/imgui_impl_opengl3.cpp
#	examples/imgui_impl_sdl.cpp
#	examples/imgui_impl_win32.cpp
#	imgui.h

About, IO: Added io.BackendPlatformName, io.BackendRendererName for informational/QA purpose.

Merge branch 'master' into viewport ...

# Conflicts:
#	imgui.cpp

Examples: OpenGL3: More explicit testing for == GL_UPPER_LEFT in case glGetIntegerv(GL_CLIP_ORIGIN is not honored properly. (#2186, #2195) Fix f52f0a5

Merge branch 'master' into viewport + comments ...

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

Examples: OpenGL3: Added support for GL 4.5's glClipControl(GL_UPPER_LEFT). (#2186)

Merge branch 'master' into viewport ...

# Conflicts:
#	imgui.cpp

Comments in demo and opengl code + Internals: Added HoveredIdNotActiveTimer tracking hovering time unless the item is active, which is a commonly useful pattern.

Merge branch 'master' into viewport ...

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

Examples: OpenGL3: Cast compile/link status to GLboolean (#2112, #2125) ...

Some OpenGL loaders/bindings do not allow comparisons between GLints and GLbooleans.

Examples: imgui_imp_opengl3.cpp explicit casting for overly aggressive glbinding compatibility. (#2112) [@hesiod]

Merge branch 'master' into viewport ...

# Conflicts:
#	examples/imgui_impl_dx9.cpp
#	examples/imgui_impl_opengl2.cpp
#	examples/imgui_impl_opengl3.cpp
#	examples/imgui_impl_vulkan.cpp

Examples: Using "dear imgui" terminology in all examples headers/comments + fix minor typo.

Merge branch 'master' into viewport ...

# Conflicts:
#	examples/example_glfw_opengl3/main.cpp
#	examples/imgui_impl_opengl3.cpp
#	imgui.cpp
#	imgui_internal.h

Examples: OpenGL: Added support for glew and glad OpenGL loaders out of the box. (#2001, #2002). Changelog, tweaks, applied changes to SDL+OpenGL3 example.

WIP on configurable OpenGL loader. (#2001, #2002)