regen/mph.pl & mk_invlists.pl - convert from sub interfaces to OO interfaces

regen/mph.pl & mk_invlists.pl - convert from sub interfaces to OO interfaces

The old sub based API was passing around an awkward number of arguments
and it was becoming difficult to enhance in certain ways. This patch
changes all the "user servicable" functions into methods, and moves the
configuration defaults into the constructor.

Note, not all the functions have been converted, the core routines with
simple interfaces have not been changed. This is OO for the purpose of
encapsulation not inheritance or overloading.