Fix inverted computation of relative x in coordsChar
Fix problem with character measuring around widgets
fix typo from 5e26b0eef41912b2ca55a3d559b80a756857fde3

cm. -> builder.cm
Cmd-Backspace should delete from the start of the line to the cursor on Mac
[extra keymap] Add, including only move-line functionality

Issue #1616
Make linter happy
[xml-fold addon] Export findMatchingTag functionality
Change representation of styles arrays

As a micro-optimization, and to prepare for the next patch.
Add getTokenTypeAt method

Use it to make xml-fold more robust, and matchbrackets much faster.
[real-world uses] Add Quivive file manager
[xml-fold addon] Add findEnclosingTag utility
Remove unused variable
[xml-fold addon] Remove another unused var
[vim keymap] Style tweaks

* simpler concat
* less escaping
* shave a line
* throw early
* throw new error
* single quotes
* format returns
* rm unneeded parens
* add whitespace
* re-add braces
[show-hint addon] Restructure

Also makes sure that no two hinting dialogs can be active at the
same time.

Issue #1619
[merge addon] Initial add
[show-hint addon] Fix problem with close event firing too late
[markdown mode] Fix bug with two links or email addresses on same line.
[test harness] Escape < and & in test input/results.
Document inputRead and keyHandled events