Fix of FIXME in getRequiredAttributes(List<Service>, Resource) in AttributesManager
 - Added method getRequiredAttributes(resource, List<Service>) in AttributesManagerBl
 - Added method getRequiredAttributes(resource, List<Service> serviceIds) in AttributesManagerImpl

 - Added test for getRequiresAttributes(sess, List<Service>, resource)
Switch group synchronizer flag to false in case of error.
Merge pull request #338 from tauceti2/groupSynchronizerFix

Switch group synchronizer flag to false in case of error.
Merge branch 'requiredAttrs' of https://github.com/papperwing/perun into kubaTask03-requiredAttrs
Fix typo and make test more complex
Merge pull request #339 from stavamichal/kubaTask03-requiredAttrs

Kuba task03 required attrs
Fix wrong data type in NotifTemplate.pm

Method getPrimaryProperties returns reference to hash not hash.

This bug caused trouble during (runtime) compilation of identity
consolidator. So when someone tries to consolidate identities he obtain
500 internal server error.