Update module header document for TH.
Update sepBy combinators.
Add binary operator `as`.
Fix binop.
Update definitions for test.
Add boolean binary operators.
Divide modules which does and does not depend on HDBC.

--HG--
rename : schema-th/src/Database/HDBC/Record/FromSql.hs => schema-th/src/Database/Record/FromSql.hs
rename : schema-th/src/Database/HDBC/Record/KeyConstraint.hs => schema-th/src/Database/Record/KeyConstraint.hs
rename : schema-th/src/Database/HDBC/Record/Persistable.hs => schema-th/src/Database/Record/Persistable.hs
rename : schema-th/src/Database/HDBC/Record/ToSql.hs => schema-th/src/Database/Record/ToSql.hs