Drag, Sliders: Merged ImGuiDragFlags back into ImGuiSliderFlags.  (#3361, #1823, #1316, #642, #1829, #3209)

Technically API breaking (but ImGuiDragFlags were pushed on master 16 hours ago)

Internals: Renamed SliderCalcRatioFromValueT() -> ScaleRatioFromValueT(), SliderCalcValueFromRatioT() -> ScaleValueFromRatioT().

Replaced drag/slider flags with a single bool is_logarithmic in those functions.

Drags, Sliders: Added deadzone to make selecting 0.0 on linear sliders easier, slider navigation delta accumulation. (#3361, #1823, #1316, #642)

Drags, Sliders: Added ImGuiDragFlags_NoInput/ImGuiSliderFlags_NoInput to disable turning widget into a text input with CTRL+Click or Nav Enter.

Drags, Sliders: Added ImGuiDragFlags_NoRoundToFormat / ImGuiSliderFlags_NoRoundToFormat flags (#642)

Drags, Sliders: Added ImGuiDragFlags_ClampOnInput/ImGuiSliderFlags_ClampOnInput flags to force clamping value when using CTRL+Click to type in a value manually. (#1829, #3209)

Drags, Sliders: Removed power features. Old entry points will pass-through if power=1.0f, otherwise assert + safe fallback. Remove 3 redirection functions (#3361, #1823, #1316, #642)

Drags, Sliders: Logarithmic: Moved flags to internals, allowing 1.0f to pass by. (#3361, #1823, #1316, #642)

Drags, Sliders: Logarithmic: Split back flags into drag/slider flags. Moved to an obsolete section. (#3361, #1823, #1316, #642)

Drags, Sliders: Logarithmic: Added logarithmic mode support to drag widgets, extended API to add flags to drag/sliders (#3361, #1823, #1316, #642)

Drags, Sliders: Logarithmic: WIP experiments with trying to make logarithmic sliders sensible (#3361, #1823, #1316, #642)

+ larger combo height on TabBarTabListPopupButton()

Fastcomp backend was introduced here: https://github.com/ocornut/imgui/commit/14b18697e653de80f75af18113033b2086846194
Emscripten changelog: https://emscripten.org/docs/introducing_emscripten/release_notes.html?highlight=2.0.0:%2008/10/2020
Emscripten issue: https://github.com/emscripten-core/emsdk/pull/590

Updated CHANGELOG.txt

CI: moved static analysis to a separate project + fix (uninitialized variable, was harmless in this case).

Amend 7b3d3798, 615e9ae3

# Conflicts:
#	imgui.cpp
#	imgui_widgets.cpp

Backends: Allegro 5: Fixed horizontal scrolling direction with mouse wheel / touch pads (#3394, #2424, #1463) [@nobody-special666]

Amend 7dea1581
+ Fix vsproj GUID

Revert "Examples: Switch most VS projects to enable Edit & Continue by default (may need to upgrade projects to latest toolchain)"

This reverts commit a24578ec.
/ZI not supported on 64-bit on some toolchains, leaving to default is best?

ImFontAtlas: Fixed multiple rebuild with same inputs erroneously increased ConfigDataCount. CI: Update Ubuntu 18.04 > 20.04 (motivated by #3369)

Fix Freetype warning.

Examples: Vulkan: Fixed GLFW+Vulkan and SDL+Vulkan clear color not being set. Broken by a06eb833 (#3390)

Vaguely relate to underlying (uncommited) work for #3291

Selectable: Fixed highlight/hit extent when used with horizontal scrolling (in or outside columns). (#3187, #3386)

# Conflicts:
#	imgui_widgets.cpp

Demo: Renamed "Layout" -> "Layout & Scrolling". Fixed usage of local struct as template class (c++11).

Scrolling: Avoid SetScroll, SetScrollFromPos functions from snapping on the edge of scroll limits. (#3379) + Demo: Rename "Layout" to "Layout & Scrolling".

Examples: Switch most VS projects to enable Edit & Continue by default (may need to upgrade projects to latest toolchain)

InvisibleButton: Made public a small selection of ImGuiButtonFlags (previously in imgui_internal.h) and allowed to pass them to InvisibleButton().

Window: Fixed clicking over an item which hovering has been disabled (e.g inhibited by a popup) from marking the window as moved.

+ comments

Fixed ImFontConfig::GlyphExtraSpacing and ImFontConfig::PixelSnapH settings being pulled from the merged/target font settings when merging fonts, instead of being pulled from the source font settings.

(effectively allowing a window to be a drag payload without have to make it _NoInputs)