stability fixes in the connector library
update submodule ref
fix compilation errors
Merge branch 'master' of github.com:dbeck/virtdb-common
update submodule ref
update submodule ref
log errors on zmq send issues()
handle or log zmq send errors
fix bool return value
Merge pull request #29 from dbeck/master

add cleanup functionality and check zmq.send return values. plus log on error