Remove diff_match_patch file from distribution, link cdnjs instead

Issue #2529
[rulers addon] Support color, width, and lineStyle options
[foldcode addon] Support foldOptions option for per-editor defaults
[show-hint addon] Add hintOptions option, sanitize interface
Prevent error when trying to find a view cutting point at end of document

Issue #2528
mode_test.js: refactor to use array of objects.
mode tests: optionally show mode state after every token.

Doesn't show states (but shouldn't crash) on old browsers.
[test runner] Top-align mode test states
Revert intentionally broken but unintentionally committed test
[cypher mode] Add UNWIND keyword