implement job state notifications for shell_job adaptor
cleanup
also communicate rc
Merge branch 'master' into feature/shell_job_notifications
improved notification support

 - fix default session on pty layer
 - allow private workdir for pty shell wrapper
 - cleaner shutdown of monitoring thread
Merge branch 'devel' into feature/shell_job_notifications
merge from devel
scattered fixes on state callbacks in shell adaptor
revert to exception on query for exit_code on incorrect state, for the time being...
merge from devel
cleanup and merge from devel
merge from devel
fixes after merge of two very divergent branching -- shell adaptor ok again