Fixed an error in the console
Support of navigator.mozTCPSocket is enabled for the main script

This object allows to use network socket to communicate with an other
server/client.

see https://developer.mozilla.org/en-US/docs/WebAPI/TCP_Socket
Fixed javascript warnings in CoffeeScript

Refs #85
New property slimer.geckoVersion
Fixed internal error during webpage.close()

The error is displayed with XulRunner 25 but it was there
longtime ago :)

Refs #85
SlimerJS is compatible with XulRunner 25b2

Closes #85
XulRunner20 and lower doesn't like tcp-socket permissions :-)