Add callback function to httpstack
Merge pull request #58 from Metaswitch/sto536_httpstack

[No reviewer] Add callback function to httpstack
Merge branch 'sto536', remote-tracking branch 'origin' into sto536
Add stats scripts
Merge pull request #61 from Metaswitch/stats_scripts

[No reviewer] Add stats scripts
Log macros should only evaluate parameters if logging enabled
Merge pull request #63 from Metaswitch/log_param_eval

[Reviewer Andy] Log macros should only evaluate parameters if logging enabled
Use correct message index for extracting successful_calls statistics from SIPp
Merge pull request #64 from Metaswitch/iss62

[No reviewer required] Use correct message index for extracting successful_calls statistics from SIPp
Merge remote-tracking branch 'origin/master' into sto536