Incorporate update to HttpStack API
Update submodule refs
Merge pull request #163 from Metaswitch/http_flows_in_sas

[Reviewer: Mike] Incorporate update to HttpStack API
Take latest sas-client
Temporarily disable a chrono logging testcase (it breaks the UTs)
Merge pull request #164 from Metaswitch/fix_uts

Temporarily disable a chronos logging testcase (it breaks the UTs)
Take latest cpp-common