Added subqueries and appropriate WHERE/AND commands to
Where() object
Broke previous api, sql(sql, params) --> sql(sqlobject)

Fixed test suite for sql objects.
Committing broken code; Adding Transaction object

Transactions: Add multiple Database Command objects to a Transaction
and if any exceptions or errors occur, rollback. Only if all are 
successful does it call commit() for you.

Broken code because the base squallsql.Sql() object is being modified
heavily for better inheritance, parameter use (more objects = better,
less strings to deal with, removal of all param () tuples)