Don't turn on the web cam until sharing is begun

src/packages/collaboration/lib/guest-session.coffee

@@ -33,6 +33,7 @@ class GuestSession
       guest = doc.get('collaborationState.guest')
       host = doc.get('collaborationState.host')
       @mediaConnection = new MediaConnection(guest, host, isHost: false)
+      @mediaConnection.start()
 
   waitForStream: (callback) ->
     @mediaConnection.waitForStream callback

src/packages/collaboration/lib/host-session.coffee

@@ -37,6 +37,7 @@ class HostSession
   start: ->
     return if @isSharing()
 
+    @mediaConnection.start()
     patrick.snapshot project.getPath(), (error, repoSnapshot) =>
       throw new Error(error) if error
 

src/packages/collaboration/lib/media-connection.coffee

@@ -13,6 +13,8 @@ class MediaConnection
   isHost: null
 
   constructor: (@local, @remote, {@isHost}={}) ->
+
+  start: ->
     constraints = {video: true, audio: true}
     navigator.webkitGetUserMedia constraints, @onUserMediaAvailable, @onUserMediaUnavailable