Merged branch 3.5 changes r510:518 into trunk.
Prepared for version 3.5.4.
Version 3.5.3
Updated release notes.
Minor change of variable order.
Added error check for getting functions.
Fixed retrieving number portability parameters issue.
Modified NP implementation.
1. Added number portability support. 2. Added diversion header support.
Merged branch 3.5 changes r504:509 into trunk.