RDKit Q42010 Open source submission

This contribution consists of three parts: 1) SaltRemover: a list of queries for standard salts along with a python function for removing those salts from molecules. This is a standard operation in preparing molecules for storage in a database. 2) FunctionalGroups: a list of queries defining standard functional groups used in chemical synthesis along with a python function for searching for those functional groups in molecules. This is useful in filtering reagents. 3) Feature invariants for Morgan fingerprints: an additional C++ function that allows the RDKit's Morgan fingerprinting algorithm to generate fingerprints similar to the FCFP fingerprints provided by Pipeline Pilot