Ict passed through to prereq types and handled.
Hide members of collapsed families properly in graph view.

Also renamed some misleadingly-named variables that dated back to before
we had collapsible families.
Warn of bad visualization node groups and members.
Merge remote branch 'upstream/master' into pre-initial-ignore

Conflicts:
	lib/cylc/config.py
Conditional simplifier added and working.
Corrected splitting of strings bug.
Cleaned print statements.
Tidied up unnecessary labels and messages.
Whitespace correction.
Merge remote branch 'upstream/master' into pre-initial-ignore
Print all visualisation warnings to stderr.
Comment and remove redundant calls to simplify.py
Merge pull request #571 from hjoliver/556.vis-validation-warnings

Warn of bad visualization node groups and members.
Fix clock triggered task

cbc86d6b560183c5a281dc6c3b8ec10691a47e02 broke clock triggered tasks.
(It only worked with clock triggered families but not individual tasks.)
Merge pull request #579 from matthewrmshin/fix-clock-trigger-task

Fix clock triggered task
Fix non-special clock trigger tasks.

Looks like f289273b26056718da530d57efc5a7aa175544ca has broken it the
other way round.
Merge remote branch 'upstream/master' into pre-initial-ignore
Merge pull request #580 from matthewrmshin/fix-special-non-clock-trigger

Fix non-special clock trigger tasks.
Merge remote branch 'upstream/master' into pre-initial-ignore
job file: fsync to file system before close

Flush and fsync job file to file system before close. This is an attempt
to prevent this type of error (seen on virtual machines) when we execute
the job file:
   /bin/bash: SCRIPT: /bin/bash: bad interpreter: Text file busy