Bugfix: stratum_works: If stratum is already active, it works (avoid trying to initialise it again)
Merge commit '8a71ea6' into bfgminer-3.0.x
Bugfix: setup_stratum_curl: Hold stratum lock until connection completes, to avoid potential races

Conflicts:
	util.c
Bugfix: Avoid unnecessary locks inside curses_print_status, which is called with the console lock held

Conflicts:
	miner.c
Bugfix: setup_stratum_curl: Need to release stratum lock on connection failure too