Add README and Travis files to scaffolded repo

[amitaibu]

Suggestion so far, and not a PR, because I'm not sure yet how to implement :)

Currently we filter out the travis file since it exists to the scaffolding repo.

However, we could do something like yeoman generator's convention and have _travis.yaml copied to .travis.yaml.

It would have been also nice, but I'm not sure if possible, if it could ask me my (optioanl) repo address - so it could auto add the Travis badge to the README

[snoyberg]

This can be implemented in the build.hs file in the master branch. I'd recommend just downloading the Travis config from:

https://github.com/commercialhaskell/stack/blob/master/doc/travis-simple.yml

[MaxGabriel]

@amitaibu I added support for adding a travis file (named __.travis.yml) to the scaffolding, if you were interested in implementing this