Fix bug: no plugin name is sent to remote nodes
Fix test execution problem on openSUSE

For some reason, locking across two calls was not working on openSUSE-based
systems. This change replaces the simple lock scheme with a condition-based
approach.
Merge branch 'master' of ssh://bitbucket.org/Dynalon/ufo-core

Conflicts:
	ufo/ufo-task-graph.c
Merge branch 'master' of ufo.kit.edu:ufo-core

Conflicts:
	ufo/ufo-task-graph.c
Abstract away communication into interface

* Create generic interface ufo_messenger_iface
* Move all zmq_* stuff into ufo_zmq_messenger that implements that
  interface
* also fixes a bug that happened when closing the zmq_socket from
  another thread by introducing a special TERMINATE message that
  will kill ufo-daemon
Merge branch 'master' of github.com:Dynalon/ufo-core
Merge branch 'master' into mpi