README update

Updates README to include a Travis build badge, which requires renaming it to README.md.
Also fixed some things in the readme.

Important note: The link for the build badge is apparently inactive.
Either this project hasn't been registered with Travis CI, or it is registered under a different name.
In the former case, please do register the project.
In the latter case, please amend this pull request so the badge link points to the correct address.