Add support for robbobases

Add support for robbobases

The UCI options RobboTripleBaseDirectory and RobboTotalBaseDirectory are
now recogized as defining the egtpath for flavors 'robbtripple' and
'robbototal', respectively. For this the general EGT-handling code had to
be adapted to be able to append 'BaseDirectory' instead of '(Tb)Path' to
the flavor for setting the option, and clipping this off for extracting
the flavor name. This is achieved by using the part of the standard option
in the list of EGT formats up to the first capital as CECP flavor name,
and match the flavor name in the egtpath command with the list, to retrieve
the full name from there.