[brace-fold addon] Allow single-line folds
[foldcode addon] Modernize interface

(Old newFoldFunction interface preserved for backwards-compatibility.)
Don't leave gaps in selection under replacedWith ranges
[show-hint addon] Change the mechanism by which keymaps are overridden

The old one was a horrible hack.
Do not call startWorker every 100ms on typing

When smth is typed into the CodeMirror editor
it schedules a job to rehighlight the next 500 lines of the document. This job
is intended to be executed in a 400ms time (as hardcoded in
`makeChangeSingleDocInEditor` method), but actually
400ms delay gets overwritten with 100ms delay which is set
from `updateDisplayInner` method.
The problem with this is that people hardly ever type 10 chars/second,
so the highlighter gets its time to rehighlight 500 lines of the
document while keydown events get postponed and user might feel some
slowleness.
Recommend standards mode for all browsers

Issue #1567
[javascript mode] Add statementIndentUnit option, tweak indentation

Issue #1553
[javascript mode] Fixup patch 69e9473b1eea76b3d9155a40c8a1c69e82c61c1d
merge