usrp_lib: setting master clock rate to 30.72 and filter to 20MHz for all cases to improve noise figure and channel response

UHD interfacing (master clock 30.72, bandwidths on 5/10/20 @ 20 MHz), RX gain calibration back to normal.

bugfixing for UL. Remaining problems: CCE allocations in subframe 5 lead to occasional illegal DCI allocations (affects UL DCI which is missed by UE). waveform compliance with CQI in ULSCH.