(+) Use AsyncWorker instead of own thread.

This is more like how its supposed to be used.
The problem was that you directly called doOnBackground. [from the
docs: „Do not call onPreExecute(), onPostExecute(Result),
doInBackground(Params...), onProgressUpdate(Progress...) manually.“]
Instead one must call execute which then does the proper scheduling.
This was already implemented in getTemperature of GenericSensor.
I disabled the precautionary illegal argument exception, to allow for
partial testing.
Remove unnecessary methods,

Make hosts, ports and paths shared. The question is where are they most
relevant and since I have to go, there are for the moment in
TemperatureActivity but they may change soon.
Add the new RequesterImpl
Merge branch 'proper-async-task'
Merge branch 'master' of https://github.com/glukas/DistributedSystemsProjects