Removed bare excepts
replaced "except as" syntax w/ 2.4 compatible comma syntax
replace assertions, raise ValueError instead
update steps to use requiredArgs
Fix failing test & shell command
check rc in a callback (errback is not called)
send headers and errno for failed fs commands
removed blank line
Merge jpommerening/buildbot:slave-fs-cmds-cleanup (PR #1066)
Merge branch 'master' into nine
make 'grunt ci' failures a warning unti #2700 is fixed
add a BuildStep.isNewStyle method
Merge branch 'master' into nine

Conflicts:
	master/buildbot/process/buildstep.py
	master/buildbot/test/unit/test_process_buildstep.py
relnotes for new-style steps
Merge branch 'master' into nine

(with minor modifications to documentation for nine)
support calling run on new-style steps
Merge branch 'master' into nine
Integration tests for custom buildsteps (backport from nine)

This includes updates to fakes and interface tests for them
Merge branch 'master' into nine