Feature/cdbi implicit inflate

Class::DBI allows the foreign_class to be a non database class. e.g DateTime.

Inflation and deflation can be controlled either by supplying:

__PACKAGE__->has_a(accessor => 'Foreign::Class', inflate => sub {}, deflate => sub {});

however if inflate isn't supplied then CDBI will call: Foreign::Class->new($val) and if deflate is not supplied it will stringify "$val".

This behaviour is mostly used for inflation and deflation of datetime columns and should be emulated