Hot fix: recent typo in batch_submit.py

Caused abort after job submission failure. The new batch submission code
now works correctly for job submission and event handler failure.
Updated change log for 5.0.1
Minor change to change log formatting.
Added missing terminal spaces in doc "make clean".
"cylc -v" for a repo returned nothing if not in repo to dir.

I hadn't noticed as I normally work from within my clone.
Bug fix doc/Makefile for missing latex commands.

The generated dependencies ('html', 'pdf') were not being used properly,
resulting in a fatal error if htlatex was not installed.
Fixed a User Guide typo.
Moved some gtk imports down to avoid display errors.

Running 'make' on a remote post-commit hook failed with "can't open
display" errors from a few commands - which this fixes.
Merge pull request #272 from hjoliver/no-X-display-for-help

Moved some gtk imports down to avoid display errors.
Merge pull request #270 from hjoliver/fix-doc-makefile-deps

Bug fix doc/Makefile for missing latex commands.
Merge pull request #269 from hjoliver/bug-fix-get-repo-version

"cylc -v" for a repo returned nothing if not in repo to dir.