more Postgres compatible database syntax changes.

[jcschaff]

more Postgres compatible database syntax changes.

• TO_NUMBER, TO_CHAR, DECODE, SYSDATE functions are not supported by Postgres, replace with newer standard functions that work for both databases (Oracle and Postgres).
• Qualified field names should not be used in a set clause of an update statement.
• Sequence syntax for Oracle and Postgres are different (there were a few places which remained hard-coded (Oracle: newseq.nextval vs Postgres: nextval('newseq') rather than using syntax from the corresponding KeyFactory.