q(...) -> Promise.resolve

```
find src spec -name '*.js' |
    xargs perl -i -pe 's/\bq(\([^(]*\))/Promise.resolve$1/'
```

src/crypto/algorithms/olm.js

@@ -60,7 +60,7 @@ OlmEncryption.prototype._ensureSession = function(roomMembers) {
 
     if (this._sessionPrepared) {
         // prep already done
-        return q();
+        return Promise.resolve();
     }
 
     const self = this;