Deprecate runahead in gcylc.rc
cylc gui: fix pure-families graph view
Merge pull request #1198 from benfitzpatrick/cylc-gui.fix-grouped-graph-crop

cylc gui: fix pure-families graph view
Update syntax highlighting keywords.
Merge pull request #1183 from matthewrmshin/refactor-job-submit

Further refactor to the batch systems logic
Merge pull request #1197 from arjclark/deprecate_gcylc_runahead

Deprecate runahead in gcylc.rc
Merge pull request #1199 from benfitzpatrick/update-syntax-highlight-keywords

Update syntax highlighting keywords
Hot-fix gcylc.rc deprecation version number.
Refactor task proxy

Remove task proxy class generation logic. Move `cylc.task_types.task` module to
`cylc.task_proxy` and rename the `task` class as `TaskProxy`. Each task proxy
is no longer its own class, but they all belong to the `TaskProxy` class.

Allow `-`, `+`, `%`, and `@` characters as task names.

Simplify logic in various places.

Reduce memory footprint.

More pep8 and pylint fixes.