Travis integration

Hi guys, done a few things here to get Travis CI to work with pyblosxom:

* Updated doctests especially in tools.py so that nosetest does not report errors
* Travis CI will auto test pyblosom with python 2.6 and 2.7. Older python not supported
* Not testing Python 3 as pyblosxom actually breaks on Python 3

See https://travis-ci.org/wari/pyblosxom/builds/14639665 for details.

Tests that requires dependencies that passes will still pass, although I believe things like acronyms test, for example should be properly set up.