Switch from travis to github ci.

[TkTech]

I needed to fix the tests for #118, since ci is failing. But the CI is using travis-ci.org, which is a dead man walking and will disappear in the next few days. So this:

• Switches from travis-ci.org to GitHub actions (however there is a branch that fixes travis here if you really want to stick with it.)
• Switches the test runner from unittest to pytest. It's compatible, and the test output is actually sane.
  • The tests become much, much cleaner after a run through unittest2pytest, but some tests are getting their indentation broken due to multi line assertion function replaced with invalid code pytest-dev/unittest2pytest#45. Don't currently have the bandwith to clean it up manually.
• Add py3.7 to py3.9 to tests.
• One test still fails before and after this change, which I haven't had a chance to look at but is probably from a change to M2Crypto if I had to hazard a guess.

While working on this, I noticed the manifest tools aren't handling newlines properly which break a number of tests for me on *nix. For example the *.mf files are using \r\n, but the tests don't normalize line endings when reading from the pipe, ex: https://github.com/obriencj/python-javatools/blob/master/tests/jarutil.py#L146 which should be NamedTemporaryFile('rt') on py3 and NamedTemporaryFile('rtU') on py2.7.

[KonstantinShemyak]

While working on this, I noticed the manifest tools aren't handling newlines properly which break a number of tests for me on *nix. For example the *.mf files are using \r\n, but the tests don't normalize line endings when reading from the pipe

@TkTech interesting, I'm running tests on Linux and getting no failures. Also, I don't see U option for NamedTemporaryFile in Python 2.7? Would you kindly file a bug?

[obriencj]

did eventually switch to actions, but using tox-gh-actions