[Tilesathome] some (internal) t at h client changes

[spaetz]

NOTE TO CLIENT DEVELOPERS:

I changed the client to use a 'Request' object in nearly all functions, rather than passing $X,$Y,$Z around all over the place.

Also  PutRequestBackToServer(X,Y,Z,Cause) is now 
$request->putBackToServer("Cause")

seems a bit cleaner to me to encapsulate this in the object.

I have committed all necessary changes, and tested that rendering and putting back jobs actually works as advertized.

spaetz