added error handling, fix for: events.js:72 throw er; // Unhandled 'erro...

Fixes [#12](https://github.com/danzajdband/moviedb/issues/12)
Added EventEmitter to emit 'error' events. You can use the following to get them:
```
var MovieDB = require('moviedb')('YOUR API KEY') 

MovieDB.on('error', function(emsg) {
  console.log("@MOVIEDB: ", emsg)
})
```