SAR deregistration changes, untested
Minor fix
Delete IMS subscriptions on deregisters regardless of HSS result code
Fix bugs caught by UT
Mark ups after review
Use an enum for the Server-Assignment-Types and change default Server-Assignment-Type when no IMPI is specified
Use the enum type on the Cx interface
Change Server Assignment Types enum name and structure
Merge pull request #25 from Metaswitch/sto635

sto635 - SAR deregistration support