fix(travis): reqs.pip -> reqs.txt
feat: tox support

tox makes it easy to verify whether tests pass across a variety of
different python versions.

This patch adds that support.
Merge pull request #128 from cabrera/travis

fix(travis): reqs.pip -> reqs.txt
Merge pull request #129 from cabrera/tox_support

feat: tox support
Remove bytes in calls to str.split()

It is useless to write foo.split(b'bar') rather than foo.split(bar). In Python
2, this is exactly the same thing:

    >>> 'fooXbar'.split('X')
    ['foo', 'bar']
    >>> 'fooXbar'.split(b'X')
    ['foo', 'bar']

In Python 3, using bytes in split() is an error:

    >>> 'fooXbar'.split('X')
    ['foo', 'bar']
    >>> 'fooXbar'.split(b'X')
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
    TypeError: Can't convert 'bytes' object to str implicitly
build master branch only
showing build for master branch only
adding urllib3 to dependencies
Merge pull request #132 from CyrilRoelandteNovance/remove_bytes_in_split

Remove bytes in calls to str.split()
Remove unused requirements

Remove requirements not directly used by the test code. These
requirements make it very difficult to determine what is actually a
dependency of the library.
Free version requirements

Tests should be run against the latest versions of libraries. Initially
there was going to be a lower bound on requirements but it is unlikely
that a situation will arise where a version is too out of date and can
be added back then rather than having arbitrary minimums.
Fix test that checks ID rather than equality

CPython does not guarantee that the id() of integers will be the same
and they should therefore be tested with standard equality.