Merge pull request #59 from materialsvirtuallab/master

Draft workflow purger.
add warning that purge workflows does not handle duplicated FWs well
for Windows compatibility, don't use os.environ["HOME"] (thanks to A. Berg)
revert undesired change in prev commit
Merge branch 'master' of github.com:materialsproject/fireworks

Conflicts:
	fireworks/scripts/lpad_run.py