JS execution with JSON serialization.
Safe JS evaluation, with logging.
JS evaluation: alert() and error line numbers.

As per #35.
' and " in file names.

Fixes in various places, template-side.
[uploader] better style, default plug is none
? and # in file names.

Please see notes in issue #38, of which this is a continuation.

In short, because of a mistake in Socket.io, files with a `?` in it won't be
editable through pencil; the OT system will actually communicate all changes to
the corresponding file name up to the `?`. We have chosen to resolve this by
distancing ourselves from Socket.io.
gateway: When creating a file, escape the name.

…before going there.
code cleanup.
Gateway: sort files by freshness.
[plugs] a few typos here and there
[404] user-added comment
Unicode fix.
404 sounds.
404: Set correct type on audio files.
gateway: unescape / in paths.
Plugs: escape paths correctly.
Root: New file types, `drivers` key.
Objective-C extension, sparql, sieve.
[mime] add svg/xml, run x-assembler and x-icon
text/plain files have type text.