Release 0.13.0

Fixes:

- Remove ETS-specific path cleaning code (#35)
- Module paths are now prepended to `sys.path` instead of appended (#26)
- Made `JobMonitor` more resilient to SMTP settings problems (#34)

Improvements:

- Improve exception handling when trying to send back job results.
- Heartbeats start before fetching input to prevent invalid crash detection
- Test against 3.4 instead of 3.3 on Travis
- Updated copyright notices to say 2014
- Add INFO-level logging messages about how jobs are running
- Switch to using `importlib` instead of using `__import__`
- Job name is no longer set using DRMAA native specification and instead uses `JobTemplate.jobName`.