Escape wiki markup.

[kfogel]

Currently, we display CSV contents in the wiki as they are. We should escape any characters that would result in wiki markup (but offer an option to turn off that escaping, so some CSVs could turn into formatted wiki text).

(Issue ticket ported here from previous repository's ticket.)

[frankduncan]

Update to this issue is that we are actively making use of this bug to do things like extra categories, wiki templates, and attachments at the driver script level. So it may have been turned into a feature.