replace q method calls with bluebird ones

```
find src test -name '*.js' |
    xargs perl -i -pe 's/q\.(all|defer|reject|delay|try|isFulfilled)\(/Promise.$1(/'
```

src/vector/platform/WebPlatform.js

@@ -68,7 +68,7 @@ export default class WebPlatform extends VectorBasePlatform {
         // annoyingly, the latest spec says this returns a
         // promise, but this is only supported in Chrome 46
         // and Firefox 47, so adapt the callback API.
-        const defer = q.defer();
+        const defer = Promise.defer();
         global.Notification.requestPermission((result) => {
             defer.resolve(result);
         });
@@ -103,7 +103,7 @@ export default class WebPlatform extends VectorBasePlatform {
     }
 
     _getVersion(): Promise<string> {
-        const deferred = q.defer();
+        const deferred = Promise.defer();
 
         // We add a cachebuster to the request to make sure that we know about
         // the most recent version on the origin server. That might not