Buffed out the datatype specifications

I'm working on a Postgres app and I needed to be able to specify a few extra things beyond what waterline can do - so I tweaked the type resolution.

Specifically: "string" shouldn't require the bulky TEXT input - instead a default of varchar(255) is pretty standard. I changed "int" to specify "int4" to avoid overflow problems. I also added "timestamptz" which is a dedicated type in Postgres specifically with a time zone. I added currency/money which specifies the common decimal(8,2) type and added tsvector for searching (which is incredibly helpful with string and text info).

Finally - rather than defaulting to "TEXT" - it makes a bit more sense to just let the type flow right through. This allows SQL dorks like me to specify "varchar(500) not null default 'hey ho hey ho'" and it will just work :).