As per irc discussion with tomprince, wrapped 'getElementsByTagName' in
try and added code for storing in Step log file. Addresses log.err issue
in pull request comment
- Changed graceful to clean.  Added also some docs.
Partial Test changes for 2419fix
- Fixed test_scripts_stop.py.  Changed short option from g to c. Fixed subfunction s/sighup/sigusr1
- Fixed stop_clean.
s/Shutdowns/Shuts down/
- Changed SIGHUP to SIGUSR1.
- Fixed documentation to reflect the new --clean parameter for stop.
Don't react to "destroy buildbot"
s/not/!=
Check against configurable nickname
- Checked if reason parameter is of type StringParameter.
- Included a check for FixedParameter.
- Added test : test_bad_reason.
Merge branch 'patch-1' of git://github.com/stchris/buildbot
Report errors for all builder at once.

This also changes all of the config error reporting to use `config.error`
instead of sometimes using `.addError`.
Merge pull request #609 from tomprince/builder-errors

Report errors for all builder at once.
Fix a couple of errors introduced by using config.error everywhere.
Lock management: store LockAccess instances in class instances

Moves some common code of converting between Lock and LockAccess to a common
place.
Add some better error handling to 'buildbot try'.

Refs #2392.