Memory leaks

[Veranika Liaukevich]

There are some places, where rasserver leaks memory.

Some examples:

• Type::getTypeStructure method returns a pointer, which should be freed by the caller. In QtMDD constructor this pointer is not freed.
• BLOBTile::initStorage duplicates FILEDATADIR string and doesn't free the memory
• QueryTree::evaluateUpdate returns a pointer to a vector, which is not freed later by the caller

In general, we should integrate a valgrind test with directql in the systemtest.

[Peter Baumann]

this seems like a substantial change, would like to hear opinions.