Merge pull request #846 from logoff/genericnetwork/circuitprovisioning

Add some model helpers and tests.
Fix compilation error related to PortSwitchStatistics refactor.
Merge pull request #848 from isartcanyameres/fix/refactor-error

Fix compilation error related to PortSwitchStatistics refactor.
Merge branch 'ofertie/refactor' of git://github.com/dana-i2cat/opennaas into genericnetwork/circuitprovisioning