Integration with Travis-CI automated build testing

Hi Santiago, 

I have been having a good time playing with the taskontrol code and getting it running on my home machine. I have also been working on integrating my branch with travis-ci, which is an automated build system. Every time I push a new commit to github, travis-ci runs tests on the code (using python-nose) and shows whether or not the build passed all of the tests. I am now in the process of writing more tests, but I am wondering whether you think that this is a good direction for the project as a whole. Using this system, any pull request would also be validated by travis-ci before it is sent to you, so that you would know exactly what type of machine the code runs on and what tests are passed. 

I also changed the README to markdown for pretty github formatting and inline images, and I moved several tests into main() functions before switching to nose for testing. 

The README for my fork contains a badge that shows the current travis build state:
![](https://travis-ci.org/nickponvert/taskontrol.svg?branch=master)

The URL for the image link will have to be changed for each fork that is synchronized with travis. 

Let me know what you think, I hope to see you Monday morning

Nick