Add an option to prevent SAS from reactivating a trail group on a marker association
Add a UT to cover the changes
Fix a bug found in UT
Tidy up UTs
Add a UT to check the no-reactivate flag is only set for a correlating marker
Merge pull request #31 from Metaswitch/no_reactivate_option

Add an option to prevent SAS from reactivating a trail group on a marker association.