0.5.5 released

[Libor Polčák]

Hello,

* Tighter content script initialization
* Bugfix: wrap `Navigator.prototype` and `Geolocation.prototype` instead of 
`navigator` and
        `navigator.geolocation`
* Remove additional Geolocation API objects when Geolocation is disabled 
completely
* Icons updated and synced with the JShelter website

Giorgio, it seems that the extension works in tests and for me menunally. But 
AMO shows warnings that runtime.sendSyncMessage, runtime.onSyncMessage were not 
implemented in Firefox. Is the NSCL code correct?

Best wishes

Libor