Added HTTP response to all methods (included commands and updates)
Now it respects HTTP specification:

it has not to return an empty list when the requested device doesn't
exist or something went wrong (and so the list is empty): it has to
return a "404 NOT FOUND" message!
Code was formatted + Error in previous commit message: I wrote "device"
instead of "building"
add version number to API URI + copyright updated
Merge branch 'master' of
http://git.elite.polito.it/montanaro/environmentapi into
montanaro/environmentapi-master

Conflicts:
	src/it/polito/elite/dog/communication/rest/environment/EnvironmentRESTEndpoint.java
Merge branch 'montanaro/environmentapi-master'
update exported API version