Fix warning in unit_access
Add debugStructure() for debugging involved structures
Merge pull request #112 from bastih/feature/debug_structure

Add debugStructure() for debugging involved structures
Add OperationData::all()
Make checked cast work as expected for production use, too
UnionAll extended with MTV optimization
added case to cast down MutableVerticalTable
Merge branch 'feature/mtv_op' of https://github.com/bastih/hyrise into feature/nested_radix_joins