Throwing exceptions is a really bad way to deal with unexpected
syntax in a highlighting mode.

Closes #2805

Bumping them for every release just adds too much git
noise and history blowup.

So that it doesn't error when inner modes are missing.

Issue #2224

Issue #2223

So that the default mode when this is loaded first is actually a
working mode.

Also: indent the file to correspond to the rest of the codebase.

Closes #2223

Issue #2221

Closes #2015

The were some minor issues w.r.t. where exactly an `stex` or `python`
inner mode starts and where the outer `rst` mode resumes; fixed.

Moving to a situation where there's only one LICENSE for the whole
distribution.

Also fixes CodeMirror.innerMode to give up on null or fixpoint

Issue #1704

Phrase-references should be able to contain interpunction characters; fixed.

Ensured that emphasis (weak & strong) plus literal syntax highlighting are rendered correctly even if the highlighted word is followed immediately by a non-word character (like an interpunction):

 * ```a word **strongly emphasised**?```;
 * ```a word *weakly emphasised*?```;
 * ```a word with ``literal emphasis``?```;

Further changed recognition order to `strong`, `weak`, `literal`, `number`, `positive`, `negative` and `link` to comply more with the reStructuredText spec (see http://docutils.sourceforge.net/docs/ref/rst/restructuredtext.html#recognition-order).

rST does not allow mixing strong with simple emphasis, further it
requires the stars to have a preceding and trailing whitespaces. Same
for literal text; e.g.

 **strong** is correct, but **strong* is not, or
 *emphasis* is correct, but *emphasis** is not.

The old mode was not supporting many rST constructs, or not in
sufficient detail. Features/changes:

 * no `backUp` ops to keep things fast;
 * kept `python` inner mode integration;
 * added `latex` inner mode;
 * eliminated `verbatim` configuration parameter;
 * eliminated non-standard tokens: the old mode was producing `footnote`
   and `citation` tokens, which were replaced with `quote`;
 * many more details: visually compare highlighting between old and new
   to get an impression;
 * MIT license (copied and adapted form `python` mode);

As spotted by the extended linter.

Closes #868

Since v2 is the canonical CodeMirror at this point

So that I can put other doc-related stuff there without polluting the
root dir.

It's tiny anyway, no need to force people to include yet another file.

This normalizes the classes used by most of the modes
(reStructuredText and diff didn't fit in), and makes them all
reference a central style sheet (under theme/). It also adds a theme
option that can be set to change the theme, and defines a few
different themes (some based on old mode colors).

- Trailing commas in object literals are not allowed by the spec
  and are handled poorly in some browsers.
- Added var to some variable declarations that were not meant to be globals.