Use "/usr/bin/env python" instead of "/usr/bin/python" for test_tools.py

[xuhdev]

No description provided.

[xuhdev]

and I also have no idea how to run the test. python test_tools.py seems not right.

[coveralls]

Coverage remained the same when pulling 5900475 on xuhdev:fix-test-tools into a0eeb5e on treyhunner:master.

[treyhunner]

I added an explanation for running the tests to the README file.

Running ./test_tools.py should work now, but python setup.py test is the recommended way to run the tests in a single version of Python.

[xuhdev]

I got this:

py2.7 runtests: commands[0]
ERROR: InvocationError: could not find executable 'coverage'
py2.7 runtests: commands[1]
ERROR: InvocationError: could not find executable 'coverage'
py2.7 runtests: commands[2]
ERROR: InvocationError: could not find executable 'coverage'

[treyhunner]

Is that from running tox with the most recent version of the code? That works for me, so I'm not sure what the problem is.

[xuhdev]

I just pulled the latest version and now it works. Thanks!