Merge pull request #9 from evoskuil/master

Resolution for issues #6, #7 & #8.
avoid creating socket repeatedly and trim old fluff from code.
we cannot share sockets among multiple threads.
default argument for fullnode_interface clients that have crypto disabled by default.
Change obworker daemon user to 'ob' (which is created in setup.sh and also used by obbalancer).
Update comments and message text to make it clear to the user and developer that setup.sh *requires* that dependencies are installed and configured in default paths (as defined by install-sx.sh).
Merge branch 'master' of github.com:spesmilo/obelisk
temporary fix for max sockets being triggered.
update for latest libczmq++ changes.