Removed power consumption related code from UWBIR.

The INET model for power consumption is different and
this code has to be ported accordingly.
Ported UWBIR related modules and classes from MiXiM to INET.

Ported parameters and some radio related functions from MiXiM's UWBIRMac to UWBIRRadio.
Added UWBIR radio to nic examples.
Changed estimation of receiving power to use the maximum value.

The decider will drop frames that have receiving power below sensitivity
and try to receive others, of course bit errors may still happen.