[docs] Remove underlines for headers
[show-hint addon] Fix bug introduced by merging 1013ebb17f89375e
[closetag addon] Fix bug in code that updated the autoCloseTags option
[javascript] Include ES6 for..of construct.
[javascript mode] More ES6 features (modules, destructuring, generators, class)
[javascript mode] Add ES6 fat-arrow support
[javascript mode] Add support for ES6-style comprehension
[javascript mode] Add support for ES6 quasiquotes
[javascript mode] Use 'extends' instead of parenthesized syntax for inheritance
[javascript mode] Fix indentation of 'else' lines

Issue #1960
[fullscreen addon] Set with to auto rather than ''
[dialog addon] Make dialogDiv accept a detached DOM node in addition to a template string
[foldgutter addon] Add options to customize change/update time spans
Add specialChars and specialCharPlaceholder options

Issue #649
Fix two bugs in f0610e60c3b220

Issue #649
Merge branch 'master' of https://github.com/marijnh/CodeMirror