Examples: Vulkan: Rewrote scissor processing to match other examples more closely. Removed extraneous +1 of scissor extent height.

Examples: Vulkan: Support draw_data->FramebufferScale correctly matching a79785c0 for on Metal/GL2/GL3. (#2306, #1676)

Examples: Removed unused variable.

Adds a style variable to Selectable that allows clients to specify the
text alignment within Selectables, adds a section in the demo to
demonstrate selectable text alignment, and a pair of sliders in the
style editor to change selectable alignment on the fly.

In terms of implementation, this one is extremely simple: Selectable was
already calling an API that supports text alignment, but had hard-coded
it to top-left. This changes that to just pass the style variable
straight through to RenderTextClipped. Backwards-compatibility is
preserved by defaulting the text_align parameter to (0, 0), i.e.,
top-left.

This also fixes a bug with selectable text rendering that caused
right-aligned text in a selectable to be clipped incorrectly, because
the wrong clipping rectangle was being used.

Examples: Extracted gamepad code into ImGui_ImplGlfw_UpdateGamepads(). Renamed matching Win32 function for consistency.
Added more link to nothing's oversample document. Spacing bits.

Causing too many subtle side-effect, e.g. IsNavInputPressed() would return true multiple times in a row.

Fixed Clang warning ("multi-line comment"). XCode also also "space between \ and carriage return". Perhaps it would work with 2 spaces? Adding a dot for now..

Scrollbar: Fade out and disable interaction when too small, in order to facilitate using the resize grab on very small window, as well as reducing visual noise/overlap. (+1 squashed commits)
Internals: Added GetScrollbarID(). (#1185)

Font: Moved functions to internal block (not enforced). Made ConfigData pointer const. Added link to stb's notes.

Changed link from https://github.com/EliasD/sfml to https://github.com/eliasdaler/sfml (no redirect + more reliable)

Font: Fixed high-level ImGui::CalcTextSize() used by most widgets from erroneously subtracting 1.0f*scale to calculated text width. Among noticeable side-effects, it would make sequences of repeated Text/SameLine calls not align the same as a single call, and create mismatch between high-level size calculation and those performed with the lower-level ImDrawList api. (#792)

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.

Examples: Metal: Removed unnecessary loop. Fixed OSX Clang warning in imstb_truetype. (#1929, #1873)

ImFont: Rearranged members toward an optimal CalcTextSize() loop. Removed comments from destructor. Made constructor more explicit.

Updated STB libraries to latest (drift has been reduced with nothings/stb as most of our changes were merged). Using [DEAR IMGUI] markers when changed.

Window: Fixed initial width of collapsed windows not taking account of contents width (broken in 1.67). (#2336, #176)

Tabs: Fixed border (when enabled) so it is aligned correctly mid-pixel and appears as bright as other borders.

DragScalarN, SliderScalarN, InputScalarN: Removed unnecessary string id after the integer PushID() calls.

Menus: Tweaked horizontal overlap between parent and child menu (to help convey relative depth) from using style.ItemSpacing.x to style.ItemInnerSpacing.x, the later being expected to be smaller. (#1086)

Added IsItemActivated() as an extension to the IsItemDeactivated/IsItemDeactivatedAfterEdit functions which are useful to implement variety of undo patterns. (#820, #956, #1875)

InputText: Fixed redo buffer exhaustion handling (rare) which could corrupt the undo character buffer. (#2333)

Plot: Register an ID to take the click the same way as other framed widgets. Set HoveredId in the FramePadding zone (between inner_bb and frame_bb).

Internals: Selectable: Fixed rendering width miscalculation when starting pos is not line start pos, which would generally be unnoticeable. Could affect group lock X with a smaller SetCursorPos value but that's unlikely to be used.

Tabs: Moved Tab List Popup to left-side to match docking button. Highlight selected tab. (#261, #351)