Adds minor MVCC improvements
* adds insert performance regression test
* MVCC: If a row is inserted and deleted in the same Tx, it is now invisible to the Tx (as it should be) - fixes #172
* Remove TXManager::getLastCID() calls from loop in Store::Merge #181
* TXManager::commitTransaction should get complete context instead of commit id only - changed rollback as well #181
Merge pull request #194 from hyrise/feature/new_mvcc

Adds minor MVCC updates
adds function for parameterized loading of (json) files
allows SortScan to order by column name (and still by column number)
adds function for parameterized loading of (json) files
allows SortScan to order by column name (and still by column number)
executeAndWait now support setting trasactionID
new tpcc test tables, and almost complete Delivery Test