Closes #581

This isn't a perfect solution, since languages can assign any class names
they want to any tokens, but I assume it covers most problems.

Closes #578

Closes #577

This was causing braces/paren/brackets in JS to match those inside of strings.

Closes #548

This is all pretty awful code. I hope to rewrite it entirely as part of
solving #305

Occurred when starting a (regular) replace below the last match.

Closes #582

This prevents situations where the cursor will cause a scrollbar, but the
rest of the code doesn't realize this. Also removes the lineSpace.style.width
setting code, which appears to have been broken in several different ways.

Closes #550

(onChange goes first now)

Autolinks were not being displayed as such in the editor, changed
'linkhref' to 'link' in line 72 to fix it.

Added support for GFM double bracket links. '[[link]]' is now displayed
correctly as a link by the editor.

Added coloring support for latex formulas, usage of
- "$formula$",
- "$$formula$$",
- "\( formula \)", and
- "\[ formula \]"
will now be highlighted with the same coloring used for strings.

% motion fails on nested parens/brackets of the same type.

Functionally no change, just much better style.

Closes #560

Fixed bug with duplicating formatted text in CSS/XML/JavaScript when only a part of the code, not the entire code, is formatted.