This reverts commit d2785a95.

This reverts commit 4b1ddfc7.

and integrated tpconfig support as well.
Fixed exception losing its initial content after appending with
getMessage() <<

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.

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.

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

Some legacy utilities from castor were imported alongside, with some adaptations.