add pytest-timeout to test runs

This adds a default 30 second timeout on every test method so that
deadlocks or broken threads are move obvious in travis. It also passes
-v by default to make things a little more verbose on where things
fail when they are failing.

requirements_test.txt

@@ -1,6 +1,7 @@
 flake8>=2.5.1
 pylint>=1.5.3
 coveralls>=1.1
-pytest>=2.6.4
+pytest>=2.8.0
 pytest-cov>=2.2.0
-betamax>=0.5.1
+pytest-timeout>=1.0.0
+betamax>=0.5.1