tigefa4u projects Trac

When upgrading an environment, a sample configuration file is written
besides the `trac.ini` in the `conf` folder.

This makes it easier for Trac administrators to manually add
the new configuration settings in the existing `trac.ini`.

It will be particularly useful for the 0.9 release, since
TracIni has evolved quite a bit since the 0.8 version ...

add enscript highlighting for Lua (fixes #1711)

Add line break before the 'replace' option on the new attachment page. Closes #1919.

Restore correct MIME type for report RSS feed that was accidentially changed in [2166].

* HTML-escape project name in title. Fixes #2000.
* Renamed HDF variable `project.name.encoded` to `project.name_encoded`. See #1915.
* Some fixes and cleanup to the report RSS feed.

Implemented wiki syntax for revision ranges.

Both `r2160:2164` and `[2160:2164]` can be used.
They will point to the Revision Log view for that range.
As such, there are similar to the log:#2160:2164 syntax.
The latter is more powerful, though, as one can restrict
the view to a given path (e.g. log:branches#2160:2164).

This closes #1259.

Setting req.hdf to None in RequestDispatcher did break out "pretty" error messages.

TracCrossReferences: modified the `TitleIndex` macro so that it also shows the count of backlinks

TracCrossReferences: merged with InterTrac (log:branches/cboos-dev/intertrac-branch#2023:2159)

Follow-up to r2160: the same fix was needed for the RSS format