Merge pull request #114 from bastih/feature/mtv_op

Add UnionAll optimization for MutableVerticalTable-nested PointerCalculators
introduced new class RecourceManager

* inherits from StorageManager, by now mostly copying it's behavior
added empty ressourcemgr_tests to units_io
added functions to AbstractRessource to check whether its an index or a table

* there may be a more elegant solution somewhere else ...
counting functions for indices, tables and resources in ResourceManager
removed isTable() and isIndex()
StorageManager now inherits from ResourceManager
added typedef for AbstractIndex
removed AlreadyExistsException from StorageManager
added lots of templates for ResourceManager

* add<>, get<>, exists<>, and assureExists<>
* for types Abstact[Table,Index(,Resource)]
used Settings class
made getInstance() work and use make_pair
almost removed old schema from StorageManager

* some tests still fail
implemented replace() in Resourcemanager and use mutex locks more consequently
cleaned Storagemanager and made size() work ... somehow
fixed: IndexScan test did not work as the StorageManagers content was deleted ...
removed preload StorageManager test
better mutex locking and fixed problem with get<AbstractIndex>()
more cleanup in Storage manager - all tests work by now :)
strange test?