Check for NULL aor_data
Make TestNonLocal test run on its own
Don't crash if ENUM not enabled
Update submodules
Merge pull request #843 from Metaswitch/update_cppcommon

No reviewer: Update submodules
Use ${MAKE} rather than make when recursing
Code review feedback
Merge pull request #841 from Metaswitch/issue839

[Reviewer Andy] Don't crash if ENUM not enabled
Merge pull request #840 from Metaswitch/issue838

[Reviewer Graeme] Issue838
Also use ${MAKE} in mk/*.mk and speed up builds of sprout-base
Remove debugging target
Merge pull request #844 from Metaswitch/better-make-recursion

Reviewer Mike - Use ${MAKE} rather than make when recursing
Merge origin/dev into sto985