Finish the new testing method

[pedrobcst]

As of currently, we have a possible new 'cif' testing method which is much faster and does not do any refinement. After the changes on how the default 'refinement' is done and modifying the simulations tests to be handled in place (when the data is being simulated), Xerus became much more stabler. The only 'test' now required is if GSASII engine can actually parse a CIF coming from a provider. The new tests justs then tries to open a CIF file using GSASII using a dummy project. This leads to a large increase of possible structures available that before were considered "system breaking".

This has to be implemented before #22.
TODO:

• Re run benchmarks using new testing method on a clean mock database.