net/py-twitter-tools: Update to 1.15.0

• Update to 1.15.0
• Add LICENSE_FILE
• Add TEST_DEPENDS and regression-test: target
• Remove GH_PROJECT (value is now the default)
• Patch tests_require and test_suite into setup.py, send upstream [1]

[1] https://github.com/sixohsix/twitter/pull/272