FELIX-3891 wait a while for concurrent registration/unregistration requests to complete

git-svn-id: https://svn.apache.org/repos/asf/felix/trunk@1453150 13f79535-47bb-0310-9956-ffa450edef68
FELIX-3915 R5 way of eliminating timing hole using changecount

git-svn-id: https://svn.apache.org/repos/asf/felix/trunk@1453151 13f79535-47bb-0310-9956-ffa450edef68
FELIX-3891 add missing apache headers

git-svn-id: https://svn.apache.org/repos/asf/felix/trunk@1453152 13f79535-47bb-0310-9956-ffa450edef68
FELIX-3952 don't hang indefinitely if a service tracking event is missing.  Add more logging

git-svn-id: https://svn.apache.org/repos/asf/felix/trunk@1453153 13f79535-47bb-0310-9956-ffa450edef68