Improved the way how the metadatas are sent from the fetch meetings info.
Merge remote-tracking branch 'fbottin/Feature1148'
Add info about the user that created a meeting in BigbluebuttonMeeting

The variable "user_creator" in BigbluebuttonRoom was moved to BigbluebuttonMeeting
as two attributes saved in the database: creator_id, creator_name
Now it's easier to find out which user created a meeting.

refs #1148