- Added func.min(), func.max(), func.sum() as "generic functions",

- Added func.min(), func.max(), func.sum() as "generic functions",
which basically allows for their return type to be determined
automatically.  Helps with dates on SQLite, decimal types,
others. [ticket:1160]

- added decimal.Decimal as an "auto-detect" type; bind parameters
and generic functions will set their type to Numeric when a
Decimal is used.