Add domthing initial demo

Howdy, what do you think about this?
Maybe I have something setup differently/incorrectly? Here's the terminal output. I can also paste `npm-debug.log` if that would help.
```
> ampersand-domthing-example@1.0.0 start /Users/dfyock/Projects/amp/examples/domthing
> beefy -t domthingify app.js


npm ERR! Darwin 14.0.0
npm ERR! argv "node" "/usr/local/bin/npm" "start"
npm ERR! node v0.10.33
npm ERR! npm  v2.1.8
npm ERR! code ELIFECYCLE
npm ERR! ampersand-domthing-example@1.0.0 start: `beefy -t domthingify app.js`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the ampersand-domthing-example@1.0.0 start script 'beefy -t domthingify app.js'.
npm ERR! This is most likely a problem with the ampersand-domthing-example package,
npm ERR! not with npm itself.
npm ERR! Tell the author that this fails on your system:
npm ERR!     beefy -t domthingify app.js
npm ERR! You can get their info via:
npm ERR!     npm owner ls ampersand-domthing-example
npm ERR! There is likely additional logging output above.

npm ERR! Please include the following file with any support request:
npm ERR!     /Users/dfyock/Projects/amp/examples/domthing/npm-debug.log
```
If I install beefy globally, I don't get an error, but nothing seems to happen?