print out data_table when verbose==2 and results are not comparable

The output for a `-v` run (`verbose==2`) is fantastic for my current use case (I'm configuring a buildbot setup for CASTEP). The output is not flooded with information and only the relevant discrepancies are printed. 

However, in the case where data is not comparable the string *"Different sets of data extracted from benchmark and test."* is output with no additional details. Since the user has no direct access to the builds and cannot do a *compare* run, it won't be easy for them to determine what went wrong.

This pull request attempts to address this by printing out the data tables when `verbose==2` and `comparable == False`.