Fixes for crashes seen when running sprout under load
Always send Ralf CDRs, even if there are no CCFs/ECFs on a SIP message (fixes #513)
Fix comment
Markups
Merge pull request #515 from Metaswitch/issue513

[Reviewer: Andy][From: Alex] Always send ACRs to Ralf.
Update cpp-common module
Merge pull request #516 from Metaswitch/update_module

[No reviewer] Update cpp-common module
Merge pull request #517 from Metaswitch/iss509

[Reviewer: Matt] Fixes for crashes seen when running sprout under load
Merge branch 'dev' of github.com:Metaswitch/sprout into iss458