Do more checks on the reg data from the HSS
Use rapidjson when writing acrs
Use rapidjson in acr UTs
Implement Memento statistics
Don't include parsing changes in pr
Merge branch 'dev' of github.com:Metaswitch/sprout into iss559
Merge pull request #889 from Metaswitch/iss559

[Reviewer: Andy] Build ACRs with rapidjson
Updates after review
Merge branch 'dev' of github.com:Metaswitch/sprout into iss591
Merge pull request #878 from Metaswitch/iss591

[Reviewer: Matt] Do more checks on the reg data from the HSS
Add UT for xml escape function
Merge pull request #892 from Metaswitch/xml_escape

No reviewer: Add UT for xml escape function
Take latest memento and cpp-common
Merge remote-tracking branch 'origin/dev' into memento-stats
Merge pull request #891 from Metaswitch/memento-stats

[Reviewer: Mike] Implement Memento statistics
Take latest cpp-common and memento
Rollup merge from Dev