Idiap change

Hi,

The code is ready for inclusion. 

The only change that is not backward compatible is for the location sensor. We modified the code so that all the location returned by the different providers during the sensing period are saved. The previous version saved only the last one (which mean that if two providers were on, only one of the two were returned)

The new sensors are:
1. PhoneRadio: information on the cell tower (gsm only)
2. ConnectionStrength: Information on the current strength of the signal (gsm only)
3. PassiveLocation: capture location that are requested by other applications and save them.

We also added copyright notice on all the file we created.

Hugues Salamin
Perhaps force-enabling the bluetooth could be extracted as a config variable. What do you think?