Multi-task selection for control commands.
Operate on families (trigger, reset, etc.) in gcylc.
Factored out some common gui code.
Exclude intermediate families from matched tasks.
Merge branch 'master' into 74.multi-task-control

Conflicts:
	lib/cylc/CylcOptionParsers.py
Merge pull request #416 from hjoliver/74.multi-task-control

74.multi task control