Add a Sass mode
[sass mode] Integrate new mode
[sass mode] Clean up missing semicolons, unused vars, and trailing space
Expose TextMarker constructor, add getOptions method to it

Issue #1111
Add overflow: auto to line widget wrapper to prevent margin leaking

(If the widget had a margin, that margin would end up outside the wrapper, throwing off
line height measurement.)

Might be related to issue #925
Support showIfHidden option in line widgets

Issue #1109
Link collapserange demo from folding demo.
Enable JS autocomplete on other variable types.

mode-javascript sets "variable-2" or "variable-3" types, too.
They should trigger autocompletion, too.

Test case:
function(obj.
Fix fat cursor
[vim keymap] Catch up on unit tests
[vim keymap] Search highlighting using overlay mode
Fix bug introduced in 47239048037dcfff0c4d34f2734d170f8330b13d
[util/collapserange] Don't depend on function definition order inside block

Closes #1128