cpp-common update
Merge pull request #76 from Metaswitch/cpp_update

[No reviewer] cpp-common update
Take latest cpp-common
Take master cpp-common
Merge remote-tracking branch 'origin/master' into update_cppc
Merge pull request #77 from Metaswitch/update_cppc

Take master cpp-common
Change Metaswitch submodule refs to ClearwaterCore