remove undocumented getStepByBuild

Its functionality is more naturally handled in getStep.
Use the Data API for build requests

This also renames the test case for the build request distributor.
update README.md with remaining buildrequest tasks
tests for PerlModuleTest
Rewrite PerModuletest to use a LogObserver
make test logfiles act more like real wrt newlines
refactor DebLintian and RpmLint to use a LogObserver
remove log.readlines
Merge branch '9/remove-getStepByBuild' of git://github.com/djmitche/buildbot into nine
Merge branch '9/use-br-data' of git://github.com/djmitche/buildbot into nine
Merge branch '9/use-data-api-5' of git://github.com/djmitche/buildbot into nine

+autopep8, pyflakes