Updates in line with recent ohNet API changes
Fix CI builds
Update ohNet dependency (to try to fix occassional valgrind errors).
Added part complete Topology4.
Added Topology3 and Topology4 unit tests to build script.
Removed group from parent when group is removed.
Merge branch 'master' of ssh://core.linn.co.uk/home/git/ohTopology
Updated L3 test to read from file.
Updated L4 code and test code.
Reverted solution file format from 12 to 11.
Updated L3 unit test and fixed some bugs that unit text picked up.
Updated test.
Made source id more specific to a group.
Fixed L2 to only event create a new source for sources that have changed. Added reference counting to L3 rooms to allow proper disposing of topology L4. Added standby to L4 room.
Updated L4 unit test.
Fixed L2 unit tests to reflect updates to L2 implementation.
Fixed L3 unit test to use Add/Remove references to L3 rooms.
Added files for L5.
Added file for TestTopology5.