1. [./Persist/Source/Source.pm] An exception should occur in table when the
   given table doesn't exist.
2. [./Persist/Driver/Memory/Memory.pm] Memory driver cannot handle filters
   where an identifier is used as the right side of a LIKE expression.
3. [./Persist/Driver/Memory/Memory.pm] Perform rudimentary checking on
   insert to make certain that the user doesn't attempt to insert
   non-scalars.
4. [./Persist/Driver/Memory/Memory.pm] Perform rudimentary checking on
   update to make certain that the user doesn't attempt to update
   non-scalars.
5. [./Persist/Driver/DBI/DBI.pm] Throughout this code all tables and field
   names should be double quoted to make sure names are compatible
   everywhere.
6. [./Persist/Driver/DBI/DBI.pm] The implicit join operation should be
   moved up into Persist::Driver as it should be essentially the same from
   driver to driver. We just have to figure out the filters to join at the
   Persist::Driver level and then provide them as an explicit join to each
   implementation.
