Change readme.txt to README.md and add travis ci support

you will need to add this repo to the ReadyTalk Travis account. I already have the README.md file set to update from yours. The build was failing for me but since I never touched the code I figure it wasn't my doing; Travis seems to be working properly. I have the bare-minimum in the .travis.yml file in the root directory; it simply gives the language of the project, you may want to make some basic changes to it.