Capture sigterm to kill hadoop jobs when worker is terminated
- whenever using subprocess.Popen, use close_fds=True
- make sure to catch errors in hdfs listdir
  (and make some minor improvements there)
- add one FIXME question
deprecate core.tmp-dir and use tempfile.mktemp instead
Generalizes exit code for captured signals
fix hdfs recursive listing with apache1 syntax
Merge pull request #250 from adregner/hdfs-lsr-apache1

fix hdfs recursive listing with apache1 syntax
Merge pull request #243 from JonNelson/improve_popen_usage

use best practices when using subprocess.Popen.  Also fix a bug in hdfs.listdir.
Merge pull request #242 from daveFNbuck/master

Capture sigterm to kill hadoop jobs when worker is terminated
Merge pull request #245 from JonNelson/use_tempfile_mktemp

Use tempfile mktemp instead of hard-coding (or relying on the user to configure something in a config file)
add TimeDeltaParameter; accepts ISO 8601 durations and n (week|day|hour|second)[s]