Add highlighting tests for Markdown mode.
[vim keymap] Reset keymap after YY is pressed

Closes #774
Fix bad arguments passed to new Line

Introduced in 846d043e9fd88afd98f8615b5df117de72242206

Closes #779
Fix XQuery demo page to not set height on scroller element

Closes #780
Remove obsolete before_script section in .travis.yml
[clojure mode] Check if +/- is immediately followed by digit before marking as leading sign

Closes #782

Correct highlighting for the following code snippet should highlight the + as an operator, and each 2 as a number (taken from http://clojuredocs.org/clojure_core/1.2.0/clojure.test/deftest)

    (is (= 4 (+ 2 2)))
Tweak context menu hack to make select-all reliable on FF

Issue #755
Fix corruption of operation data introduced by 6ba24813c96687dac2f23db100780bc42e6ed808
Add addLineWidget/removeLineWidget API functions
Add getLineNumber method
Use on/off instead of connect/disconnect for event registration

The off pun is rather awful, but it does have precedent, and is
more succinct.
Add CodeMirror.version to API

Closes #781
Fix link in widget demo
Move back to padding for scrollbar-hiding

Add heightForcer hack to solve glitches.

Closes #798
Missing semicolon
[shell mode] Fix unsafe use of object

Parsing the word constructor would look up words["constructor"], and
return Object.prototype.constructor instead of a style string.

Closes #793
[markdown mode] Improvements to parsing and tester

(Squashed commit. Below are the original commit messages:)

- Add highlighting test for Markdown for consecutive backticks.

- Make it possible to wrap inline code in multiple backticks.

- Add highlighting test for Markdown mode to only allow a single space
  to separate brackets.

- Make it possible to separate bracket groups with a space.

- Allow for horizontal rules to use dashes.

- Allow for *any* number of -'s or ='s for setex headers.

- Remove requirement that the text for setext headers have to be
  highlighted.

- Might revisit someday to work on this, but in the meantime, it's
  better to prevent regressions than to be picky about what would be
  highlighted in an ideal world.

- Correctly match single line footnotes with title.

- Match inline links in Markdown mode.

- Don't match unclosed code blocks.

- Get mode test highlighter in line with CodeMirror.highlight().

- It would be nice to use all native functions, to avoid having to update this manually each time.

- Fix tests per fixes made to mode test highlighter.

- Properly handle multiple classes for mode tests.

- More correct handling of EM and STRONG in Markdown mode.

  Per Markdown documentation: "You can use whichever style you prefer;
  the lone restriction is that the same character must be used to open
  and close an emphasis span." # This is the 15th commit message:

- Allow escaping of * and _ by surrounding with spaces.

  Per Markdown documentation:

  "But if you surround an * or _ with spaces, it’ll be treated as a
  literal asterisk or underscore."

- More correct support for inline code blocks.

- Adjust Markdown highlighting tests to fit readability, rather than
  100% conformance with Markdown documentation.

  Although unclosed italics, bold, and inline code would not be
  formatted by a Markdown parser, it is extremely helpful to have the
  styles added even when it is not yet closed. It may be a good idea
  to add an 'incomplete' flag for each at some point, in order to
  style it (and mark it) as different. Perhaps piggyback off of
  "error".
Fix widget demo on IE9

There's apparently a timing issue with adding widgets to
a just-initialized editor.
Give non-inline line widgets a width corresponding to the width of the editor

Closes #792
Closes #788
[widget demo] Wrap widget updates in operation() call

This seems to be a better fix for the scroll artifacts.

Closes #795