Closes #776

Closes #773

Closes #768

The hack is horrible, but it seems to do the trick.

Also simplifies context-menu handling somewhat.

Issue #755

Some things appear to trigger it to scroll, with very bad
effects.

(And codemirror.css from a relative link.)

Closes #756

Closes #759

Closes #761

Closes #764

Fix bad rules in themes, measure width correctly.

Closes #765

It was passing undefined to setTimeout.

Closes #763

Closes #760 and fixes line backgrounds ending up behind editor background.

Discussion in issue #762

By clipping its top/bot to the borders of the outer div

The previous one broke line numbers

A *real* cleanup / reorder is becoming painfully needed, but this'll at
least make the tests pass.

Add CodeMirror.defineOption function for defining new options.

Add findMatchingBracket to the methods exported by this extension.

Closes #746

Prevents styled backgrounds from hiding the selection

It is now more structured (knows about ranges) and allows automatic
unfolding when the cursor enters the folded range.

This allows multiple handlers to listen for a single event, and makes
the API a bit more uniform.

Issue #725

Makes Hebrew text mostly usable

This will make fixedGutter work properly, and make it the only model
(no more gutter that scrolls out of view).

Also reorganizes the basic css file to be easier to modify for users.

Issue #730

Issue #294

Get rid of eolSpanContent mess.

Preparation for RTL text handling.

No more random {x,y,yBot} thrown into the mix.

Experimental for now.

- Multiple gutters are explicitly created with the gutters
  option
- Markers go into a specific gutter, new setGutterMarker,
  clearGutter methods
- The line number gutter is separate
- The 'fixedGutter' feature is removed (painful to do now,
  was shaky anyway)

Closes #738

Closes #753

Closes #751