[ruby mode] Fixes /= operator for highlighting

relates to https://github.com/marijnh/CodeMirror/issues/314
[markdown-fold addon] Add
[markdown-fold addon] Add support for undelined headers

Issue #2253
[vim] Translate regex backreferences from vim form to javascript form

... so that users can use \1, \2, etc in the replace expressions.
Use a saner (and cheaper) way to pad the selection

Issue #2256
[searchcursor addon] Refuse to search for queries that match everything

It doesn't do anything useful, and makes replace-all loop
forever.

Closes #2259
Make deleteLine delete the whole line with \n.
Move query-checking logic to search.js

The vim mode was making sensible use of a searchcursor with
a match-everything regexp as cursor.

Issue #2259
Make sure a mouseclick causes a resetInput on IE9

Issue #2260
Fix drag-selection on IE9

It apparently does not have a working buttons property on its mouse
events.
[xml mode] Make it actually possible to disable multilineTagIndentPastTag

Closes #2262
[solarized theme] Fixing tab character visual

Doesn't take up any space now, so that a tab of width 2 is 2 em width
rather than 3.
[show-hint addon] Default to hinting with anyword, when nothing else is found

(Only works if anyword-hint.js is loaded.)
[yaml-lint addon] Add

Added a wrapper for js-yaml.js to enable YAML lint support. Followed
json-lint.js pattern. Unfortunately js-yaml.js only shows one error at
a time, but something is better nothing. Checked code with linter and
ran tests. All came back clean.
[sold mode] Add
[search addon] Fix replacement of multiple groups

Closes #2268
[octave mode] added more builtins, fixed comments

(removed non-octave ... comments, added octave's # comments)
Fix resolveMode's handling of MIME types in name fields

Also configure the htmlmixed option to pass through xml-mode-specific
options to its inner xml mode.

Issue #2265
Make by-group motion stop after groups of 1+ space, newlines

Issue #2255
Use a transparent border on the sizer to force scroll width

This produces saner widths for most elements, and removes
the need for the border/fit-width hack on the pre elements.

Issue #2256

Conflicts:
	lib/codemirror.js