1. [./Persist/Persist.pm] For this documentation (or somewhere) list those
   keywords that should be avoided because they are a part of ANSI SQL or a
   specific driver's implementation--that is, they shouldn't be used for
   table or column names.
2. [./Persist/Table/Table.pm] When calling save add checking to make sure
   such a call is legal.
3. [./Persist/Filter/Filter.pm] Add a direct date syntax instead of using
   the rather klugey string-magically-becomes-a-date-when-needed semantics.
4. [./Persist/Driver/Driver.pm] We need an API to allow for the discovery
   of what parameters are necessary for creating/deleting/connecting to
   sources. Perhaps something similar to a table definition to take
   advantage of our metadata system.
5. [./Persist/Driver/Driver.pm] Design a way for update to perform a
   filtered update. That is, it would be nifty to do something like
   update('table', value => sub { $_ + 1 }) or something similar that could
   be used by the back-end in the most appropriate way.
6. [./Persist/Driver/Memory/Memory.pm] This is bad, we don't want to parse
   the date at every use!
7. [./Persist/Driver/DBI/PostgreSQL/PostgreSQL.pm] Combine common code in
   first and next.
