Implemented WebDAV <-> Filemanager interaction.

Each project (ProjectDirectory) has 2 subdirectories, one called Subprojects
(SubprojectsDirectory) with all suprojects and one called "File entries"
(FilemanagersDirectory, plural) with a subdirectory for each filemanager item
(FilemanagerDirectory, singular). The files are represented by FilemanagerFile
objects.

The user can modify the webdav tree according to these rules, which causes
filemanager items to be created, updated and deleted accordingly. Additions that
don't fit this pattern won't be accepted. Instead, a 501 Not Implemented is sent
to the client.
correct typo
Set upload as not required

When the user creates a directory via webdav, he can't directly add files.
In order to be able to create filemanager entries via webdav, we must allow
empty filemanager items.
Fix test data

Old module versions triggered migrations which caused us to call die()
Added unittests for webdav
Fixed include in EmptyDir
Removed empty constructor
use $hash instead of $md5 to please checkstyle
Do not call Sabre_FS_File->delete, $filemanager->save does that for us.
Added upload folder in test private dir, it is needed for webdav tests
Make filemanager titles in tests unique

They're used in webdav tests and the db forces them to be unique in the current
next, so I might as well change them now.
Added Phprojekt_Exception_IOException
Merge remote-tracking branch 'mayflower/next' into unifyWebdavAndFilemanager-296
    This should fix travis

* mayflower/next:
  Fix paths for travis
  Test Travis
  We do not offer 26 languages.
Merge remote-tracking branch 'mayflower/next' into unifyWebdavAndFilemanager-296

* mayflower/next: (53 commits)
  Style
  Remove left-overs from caching in Phprojekt_Tree_Node_Database
  Put the real project in the registry and allow it to be retrieved.
  Throw an exception if the project given to setCurrentProjectId does not exist
  Use the correct path in our coverage whitelist
  Added some .gitignores
  Use correct version in filemanager migration
  Updated tests to work with unique filemanager and project names
  Make filemanager titles unique
  make project titles unique
  Removed fromVObject from Timecard_Models_Timecard
  Use VObjectReader instead of fromVObject in Timecard Calendar backend
  Added VObject Reader with tests
  Only recognize Project numbers in brackets if they're at the end.
  Corrected some whitespaces
  Add test to check that we prefer the id over the name
  Recognize numbers in brackets as project ids and prefer them over the names
  Handle "Unassigned" seperately when reading tcc vevents
  Added a bunch of tests
  Always use ->value of sabre vobject elements
  ...

Conflicts:
	phprojekt/application/Filemanager/Migration.php
        Use Migration which makes titles unique

	phprojekt/tests/UnitTests/Default/data.xml
        and
	phprojekt/tests/UnitTests/common.xml
        Use all test data
Add upload path to travis configuration
Minor style fix in filemanager migration
Make filenames unique in filemanager migration
Fix the Db.json file broken by the commit that made update not required
Make filenames unique in the upload helper.

This reflects on the forms.
Validate that filenames are unique in Filemanager_Models_Filemanager