Web sceenic-plugin v0.0.1-alpha.7

What's New:

• change SceenicEvent to VideoRoomEvent.
• change addSceenicEventListener to addVideoRoomEventListener.
• change removeSceenicEventListener to removeVideoRoomEventListener.
• add VideoRoomEvent.ERROR event to attach and remove listener for error events.
• show UI errors for sceenic-video-room element.