Deploying to Github Pages with Travis

This is mostly for my benefit as I always have to look it up - this will push content that's built by your Travis build into the gh-pages branch of the same repo. It's the simplest way of deploying to Github Pages I've found - it handles switching branch and details like pushing content from a dist subfolder for you automatically.

Install the gh-pages CLI tool using NPM:
```
npm i --save-dev gh-pages
```
Grab a Github access token so Travis can push back up to your repo's gh-pages branch:
- Go to https://github.com/settings/tokens/new and create a new token with the full repo scope.
Encrypt the token with Travis so you can use it in your builds (--add automatically adds the encrypted data to your travis.yml):
```
travis encrypt --add -r <org/repo> GITHUB_TOKEN=<token>
```
- If you don't have travis available on your machine, use gem install travis.
Finally, Travis needs to know how to use the token when pushing. As a step in your .travis.yml:
```
script:
...
- git remote set-url origin https://<token's username>:$GITHUB_TOKEN@github.com/<org/repo>.git
- gh-pages -d dist
```
- Add any other args for gh-pages as necessary - the above will put all the content in the dist folder into the root of the gh-pages branch.