Fix Travis CI build process for deployment

[flowirtz]

Travis fails doing the build, however it works locally. I tried to fix this in a fork. This did not work out however.

How deployment works atm

One builds locally (see README for reference) and then pushes the master branch to GitHub. Travis will then deploy the dist folder to gh_pages.

How it should be done

Travis does the build and then pushes the result to gh_pages. This in theory can be achieved by just calling npm run build-deploy and then pushing the result in dist, e.g. by using ngh.

The problem

Either npm install or the build fails, that unfortunately differs. I experienced both.

[flowirtz]

Also see e61d86c and #15