Added errors for pregel conductor
Graph in frontend
Conductor finished step implementation. Included error cases in tests
Merge branch 'pregel' of github.com:triAGENS/ArangoDB into pregel
Finished implementing all error cases on finished Step
Merge branch 'pregel' of github.com:triAGENS/ArangoDB into pregel

Conflicts:
	js/server/tests/pregel-conductor-spec.js
Merge branch 'pregel' of github.com:triAGENS/ArangoDB into pregel
Merge branch 'pregel' of github.com:triAGENS/ArangoDB into pregel
First attempt for single server communication in pregel
Merge branch 'pregel' of github.com:triAGENS/ArangoDB into pregel

Conflicts:
	js/server/modules/org/arangodb/pregel/conductor.js
Commented self request in single server pregel