Gridmap

- Vastly more reliable job completion information thanks to switch back to
using 0MQ for communication with worker nodes. No more unpickling
exceptions because the SGE DRMAA implementation frequently liked to say
jobs were finished when they were not.
- Add back web monitor to report basic job status.
- Switch to using custom fork of drmaa-python until
drmaa-python/drmaa-python4, which fixes Python 3 compatibility issues,
gets merged.
- Now creates temporary directory for storing log files if it doesn't
exist.
- Travis-CI SGE installation has been streamlined.
- Switch to using sphinx and readthedocs for documentation.
- Added detection of stalled jobs. GridMap will also automatically restart
any jobs that appear stuck (up to 3 times by default), and email you a
report describing their CPU and memory usage over time.

- Fix issue where `clean_path` wasn't being called on the working
directory, which was causing ETS-specific issues.
- Add a couple workarounds for issues with setting environment variables in
Python 3.
- Made examples into unit tests and added first attempt at getting Travis
setup with SGE.

- Working directory is now correctly set for each job.
- Simplified handling of environment variables. Should now all be passed on
properly.

- Can now import `JobException` directly from `gridmap` package instead
of having to import from `gridmap.job`.

- Now raise a `JobException` instead of an `Exception` when one of the jobs has crashed.
- Fixed potential pip installation issue from importing package for version number.

- Changed way job results are retrieved to be a bit more efficient in cases of errors.
- All job metadata is now retrieved before job output is, which should hopefully alleviate issues where we can't get the metadata because its been flushed too quickly by the grid engine.