broke out _defaultMessageURLs()

Broke out code for adding URLs to a build result email
from buildbot.status.mail.defaultMessage() function into
a new function.
unit test on mail.defaultMessage() function

Added unit test on buildbot.status.mail.defaultMessage() function
Add LineConsumerLogObserver
refactor python steps to not use log.getText
factor getText out of pbuilder.py
remove uses of log.getText from shell.py
factor getText out of Trial and HLint

This introduces rudimentary tests for HLint.  I don't have a sample of
output from this command, so I can't write any more comprehensive tests.
factor getText out of Mock and RpmBuild
remove regex_log_evalutator
remove fake log.getText method
notes to update documentation when everything is settled
finish unfinished comment
Merge branch '9/use-data-api-6' of git://github.com/djmitche/buildbot into nine
remove log_eval_func

This was undocumented, apparently mostly unused, and mostly redundant to
evaluateCommand, but took a step status object as an argument.
Implement compatibility for read-only log methods in old-style steps

Including
 * log.getText, log.readlines, etc.
 * step.getLog returns an instance with those methods in old-style
   steps
fix TODOs for log observers
Merge branch 'git-poll-3' of git://github.com/jhol/buildbot (PR #1010)
Merge branch 'delivery' of git://github.com/krf/buildbot (PR #1038)
Merge elmirjagudin/buildbot:mail-utests (PR #1039)
factor out assertRegexpMatches, which doesn't exist in 2.6