Bug 1049569 - Sanitize e.me app url results. r=francisco

e.me app result urls often miss the trailing slash. Sanitize them so we get better bookmarking behaviour in the system browser.
Code below works perfect, my suggestion is purely aesthetic, we can have an utility function (not exposed in the api) like:
`function sanitizeResults(emeResults)`

Inside we do:
`return new Promise(function(resolve, reject) {
 // ... code already done for sanitization
 resolve(results);
})`

and then we can call directly:
`return Request('Apps', 'search', options).then(sanitizeResults)`