Moved all of the classes in middletier/common to the scheduler directory because most of them are specific to the scheduler.  Please feel free to move those that are no so specific elsewhere.

Replaced a static const by an hardcoded value to avoid statis object initialization order issues in the unit test.

Fixed memomy management of the unit test, and disabled the object store middle tier unit test, which crashes on initialization.

Added compilation of object store middle tier. The unit test cannot compile yet (commented out) as the classes are not fully implemented.

Ported the directory creation of Vfs to MockNameServer, so the unit tests can pass in the presence of leftover temporary files.

middletier, itself separated in interface, SQLite, objectstore and
shared tests.
Moved all utilities (exceptions, threading...) to a shared utility
directory.
Created a single, shared unit test from all the scattered ones.

Ported the user tests to the new structure.

Used exceptions while moving Vfs to creating its temporary directory using mkdtemp. This allows several Vfs intances to run on the same
system simultaneously.
Updated the model of the abstract unit test so it can instanciate one test environement per unit test. This was needed in the current
unit test for middle tier admin.

Duplicated the SQL middle tier unit tests and turned them into templated tests for re-use with other implementations of middle tier.

License comment is no longer filtered out by doxygen when generating web pages of the individual source files.

Moved previous versions of object store tests in a diffrent directory. They will eventually be removed.