[#11] Updated extend functionality

Details:
* Updated attributes
* Removed ready callback from base Polymer
* Added new default attrs to connection
* Added unique ready call to connection

Note: I think ready was the issue but unsure.
      All I know is that these changes fixed the issue.
[#5] Created external script containers & added room getters

Details:
* Externalized JavaScript in accordance with CSP security
* Added connection#rooms
* Added connection#room#get
[#2] Added Room Element

Details:
* Added goinstant-room container
* Updated Demo