rtl_power: more bug fixes
rtl_test: generic tuner range test

This scans 0 - 3GHz looking for frequencies that can be tuned to without
error, and refines the band edges further once a tuneable band is found. It
should work with any tuner that correctly reports tuning errors. It takes
about 1.5 minutes to complete on a R820T.
r82xx: enforce PLL register limits.

This fixes out-of-range frequencies that would set the PLL
registers to incorrect values rather than failing outright.
rtl_fm: link librt
rtl_test: refactor tuner_benchmark
rtl_fm: handle no availible buffers
rtl_fm: arbitrary translation prototype
rtl_fm: remove unused resamplers
rtl_fm: software agc
rtl_fm: sw-agc quantization correction