When you run 'python -V' under Anaconda, it
returns for example, 'Python 3.4.3 :: Continuum
Analytics, Inc.' However, the original parsing
of the version in 'test_f2py' assumed there was
nothing following the version number, causing a
ValueError because you can't assign three
variables to four components that you get from
splitting on the '.'

The 'sys.executable' can come in various names, but
the three main ones are "python", "python{major_version}",
and "python{major_version.minor_version}". The current
version of the f2py test assumes that only the latter
two are used. Since "f2py" is generally versioned,
using the executable basename "python" will make it
impossible to find. This commit fixes that issue
by using a sure-fire way of getting the Python version.

Fixed test_scripts.test_f2py test so that
it can pass correctly on win32 virtualenvs,
in which the Python executable and the
f2py.py file are both in the Scripts
directory.

The test was checking whether the f2py script was installed as either of
two names, but was only catching OSError, so the second check was
skipped if the first failed for another reason. The caused the
runtests.py script to fail it does not install the script as f2py but
rather with the python version appended.

Also rewrite error messages so that they read more like warnings
than errors.

Module tests whether we can run f2py and return correct version.

Skip this test when running in-place (we don't install f2py in that
case).

Use our own virtualenvs in travis-ci to avoid picking up travis' numpy.