tigefa4u projects Trac

Fix support of space characters in paths. This concerns `mod_python` when the `TracUriRoot` directive is used. Closes #2864.

Applied patch for #2899. Thanks pacopablo.

Some follow-up to r3092 and r3094 for the TracChangeset ''diff'' format (either old_node or new_node could be None) and ''zip'' format (better comment)

`trac.util.markup.Fragment` objects can be directly attached to the HDF

More unicode fixes for TracChangeset diff and zip formats

Follow-up to r3092: also convert attachments content to unicode before handing it over to `preview_to_hdf`.

More unicode fixes for the TracChangeset and TracBrowser modules.

* Perform the diffs in unicode. In changeset.py, we convert
the file content to unicode before the diffs are computed.
Should fix #2905 and #2363.
* Clarified some assumptions made in the mimeview component.
Unless stated otherwise, strings should be unicode strings.
This is particularly true for the `preview_to_hdf` method.
Therefore, in browser.py we have to convert to unicode as well.

Both of the above make use of the following:
* a new `Mimeview.to_unicode` method which uses the standard
Mimeview ways to infer the charset from either the content
type or from the content itself
* the above makes use of a new `to_unicode` function in `trac.util`
which always succeeds at producing an unicode string

I also made clear that when using `trac.util.NaivePopen`,
a properly encoded string must be given. I couldn't fully
test the corresponding changes in enscript.py and php.py, yet.

Use `repr` instead of `str` in order to build some unique identifier in the `check_modified` code. This makes it immune to encoding issues. Closes #2963.

Fix some unicode issues for the TracSubversion backend.

* Make conversions to and from Subversion's UTF-8 encoded strings more obvious,
using `_from_svn` and `_to_svn` functions
* The `_to_svn` enables also to clarify and simplify the code related to
scoped repositories
* A few other little fixes were needed in the modules

Note that content related issues are not addressed by this change
(the diff issues of #2905).

Added tests for the `SubversionRepository.previous_rev/next_rev` methods using and additional path argument