Clean up the way suite environment variables get to the job script.

 * handle static and task-host-specific variables separately
 * pass the environment dicts directly to jobfile module
Same for the submit command.
Merge branch 'master' into suite-env-housekeeping
cylc/cylc#415: fix localhost background submit.

localhost job submit: add bracket around the command to prevent
incorrect pipings.
In UTC mode, set environment variable TZ=UTC.
Merge pull request #418 from matthewrmshin/utc+

In UTC mode, set environment variable TZ=UTC.
Merge pull request #417 from matthewrmshin/415.fix.job-submit-local

Fix localhost background submit
Officially drop Python 2.4 support, which is already broken.

Closes #389. This commit just:
 * updates the user guide "requirements" section;
 * removes a few back-ports of the python 2.5 'any' statement
Allow prep commands to take a file path instead of suite name.

Closes #419.
Same for get-config command.
Handle commands with no suite arg (e.g. scan).
Better variable name.
Merge pull request #420 from hjoliver/389.drop-python-2.4

Officially drop Python 2.4 support, which is already broken.
Update cug.tex

Fix missing close curly brace.
Fix previous merge.
Merge branch 'master' into suite-env-housekeeping
Merge pull request #409 from hjoliver/suite-env-housekeeping

Clean up the way suite environment variables get to the job script.
Fix search command for file path arg.
Updated in-source comments in old event handler submission module.
Take cylc-suite-env write out of task jobfiles.