Fix wrong file name for travis

Should be .yml, not .yaml!
Add the build icon to the README

Adds the result of the last travis build to the README, to display on
github.
Link the build image to travis

Clicking the button now takes you to the ScottLogic/insight page on
travis, where you can see build histories
Hook grunt into travis

We want to run grunt for our own unit tests as CI.
Also makes the "deploy" action run tests and generate docs.

The default action now builds on the deploy action, doing "all of the
above" plus watching the project.
Merge pull request #47 from tpkelly/master

Add CI properly