Travis doesn't support 3.4, so I'm removing it ONLY from the travis config file.

Travis DOES support 2.6, but linker does NOT work w/2.6 (or rather the tests
won't run in 2.6 to confirm whether it works with 2.6 or not). As a result, I've
removed 2.6 from the travis config, the setup.py classifiers, and the README.