While there is separate handling for `except` and `else` of a `try`
block, they don't seem to be doing anything significantly different. So
just use a `finally` statement instead and drop `except` and `else`.

As `run_bulk_job` can sometimes raise a `StopIteration` and this is
deprecated behavior, catch and squash this exception. Thus avoiding the
deprecated behavior. As this still breaks the loop and ends the
generator, this has no real effect on how this generator behaves.

Travis CI has made the default Ubuntu Trusty and will soon eliminate
Ubuntu Precise. For now, require Ubuntu Precise. At some point this will
need to be rewritten to use Ubuntu Trusty or will need a Docker
container that can mimic the original system for testing.

Require Ubuntu Precise

…_finally_run_bulk_job'

Use `finally` in `run_bulk_job` and catch StopIteration

Was named `wheel` previously, but should be named `bdist_wheel` as that
is the subcommand that this argument is being passed to.

ref: https://wheel.readthedocs.io/en/stable/#defining-the-python-version

Makes sure the license file gets included in the wheel so that is
available for the end user to inspect in the installed environment.

Fixes for wheels

As Python 2.6 has passed its EOL (back in 2013), go ahead and drop it.

Python 3.3's EOL was last September. So drop support for it.

Drop Python 2.6

Drop Python 3.3

Adds the Python 3.7 dev release as a target of the testing matrix on
Travis CI.

ref: https://travis-ci.org/pygridtools/drmaa-python/jobs/409174795
xref: pypa/setuptools#1257

Start testing against Python 3.7

Update version number.