SQLGetTypeInfo

Implement SQLGetTypeInfo. Returns information about types. 

Spec: http://msdn.microsoft.com/en-us/library/ms714632(v=vs.85).aspx

This is the last catalog function. Doing a quick search, there's no more functions that select from Postgres's information schema. After implementing SQLGetInfo (which is a bunch of parameters about what the DB is capable of), we can talk about next steps (testing against an example ODBC app?)