suzerain: draft implicits

Following instantaneous and reference, add something
to track just implicit values to provide better eventual
grouping within the to-be-revamped operator_common_block.

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@45069 0bd85f0b-c151-43b9-a1e9-27231104551f
suzerain: permit use as base classes

Rationale is that the same memory block/logic could be extended
for the reacting case some day, and the overhead for these
particular virtual calls is entirely moot.

Also, gives an excuse to have a cpp file hiding the constructors.

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@45070 0bd85f0b-c151-43b9-a1e9-27231104551f