tree portlet: use URL instead of path.

In order to respect virtual host monster configuration and other custom URLs
we need to build the links in the portlet with URLs instead of paths.
Add separate profile with the gever specific mimetypes.

This fix the mimetype icons bug.
Merge pull request #596 from 4teamwork/jone-tree-with-urls

tree portlet: use URL instead of path.
Use ftw.testing implementation to disable plone snapshots during tests.

Closes #592.
Merge pull request #597 from 4teamwork/deif-use-testing-patcher

Use ftw.testing implementation to disable plone snapshots during tests.
Fixed encoding issues in the `EmailContactsAndUsersVocabularyFactory`.

The OGDS always return unicode because of our mysql connection string:

```
mysql://opengever:opengever@localhost/opengever?charset=utf8"
```

MySQLdb requires a “charset” parameter to be passed in order for it to handle non-ASCII characters correctly. When this parameter is passed, MySQLdb will also implicitly set the “use_unicode” flag to true, which means that it will return Python unicode objects instead of bytestrings (See http://docs.sqlalchemy.org/en/latest/dialects/mysql.html#module-sqlalchemy.dialects.mysql.mysqldb fore more informations).
Merge pull request #599 from 4teamwork/pg_vocabulary_encoding_fix

Fixed encoding issues in the `EmailContactsAndUsersVocabularyFactory`.
Merge pull request #598 from 4teamwork/pg_mimetype_icons_fix

Add separate profile with the gever specific mimetypes registry entries.
Hide ftw.mail.mail-in viewlet, yet again.

Plonetheme.teamraum has its own skinname, thus we need to remove the viewlet for
that skin as well.
AdminUnit table: Added upgradestep for the new abbreviation column.

See https://github.com/4teamwork/opengever.ogds.models/pull/24 for more informations.
Referencenumber: use current admin_units abbreviation instead of the label for the PloneSite part.
PEP8.
Merge pull request #600 from 4teamwork/pg_abbreviation_column

PloneSite referencenumber: use current admin_units abbreviation instead of the label.
Merge pull request #602 from 4teamwork/deif-hide-mail-in-viewlet

Hide ftw.mail.mail-in viewlet, yet again.
Fix printing error message for dossiers with non-unicode chars in title.

Fixes #589.
Merge pull request #603 from 4teamwork/deif-fix-deactivate

Fix printing error message for dossiers with non-unicode chars in title.
LaTeX layout: use current admin_units label instead of the current org_unit as client title.
Merge pull request #604 from 4teamwork/pg_latex_client_title

LaTeX layout client title: use current `AdminUnits` label.
Use ftw.table from source.
Treeportlet: define context-url data object instead of context-path.

This is a follow up of #596: During the changes to support virtualhostmonster configurations, the tree data has changed from path to url. But to adjust the data attribute, was forgotten.

Additional i've added some small tests for the treeportlet itself.