tigefa4u projects Trac

Make it possible to examine ticket description changes (#2945).

It is now possible to look at the history of the ticket description field and to visualize the actual changes.
It is also possible to view a ticket at a specified version, in read-only mode.

Next to the ''Description (last modified by <author>)'' title, there's now a (diff) link for showing the differences.
Each description change in the regular change history also features such a (diff) link.

From the diff page, one can go to a ''Ticket History'' view similar to the one of the Wiki page history, this one listing the changes for the ticket description field. From the history view, on can jump to a specific version of the ticket.

Enable `add_stylesheet` etc to generate links outside the `chrome` path: if they start with a slash, they're considered relative to the application root URL, otherwise the link gets prefixed with `chrome/`.

Blocked r3857,r4189,r4296:4297,r4331,r4333:4336,r4339 from being merged, via svnmerge.

0.10.3dev: Ported r4332 (''cleanup PHP highlighter'')

0.10.3dev: Ported r4042 and r4330 (#3971)

0.10.3dev: Ported r4341, tentative fix for #3645 (''MySQL disconnect'')

Attempt to fix the MySQL disconnect issue (#3645). Thanks to Scott MacVicar for the idea of using `ping`.

SpamFilter plugin: changed the attachment adapter to not filter binary attachment data. Should close #4087.

Add MySQL version to the system info.

0.10.3dev: Ported r4337, fix for #4204 (''resync broken'')