fix carriers initialization

make sure tested process won't exit before killing it
dsp: Filter should hold processing state
dsp: remove unused code
dsp: fix Demux sampling handling
equalizer: fix gain handling and remove dead code
recv: fix --skip default values
recv: constellation should use '.' (instead of '.:')
recv: require 99% for coherence and 99% of carrier duration
send: fix training and signal generation
recv: fix UT
test_full: use more ppm values (+/-)
equalizer: add lookahead estimation
use equalization at receiver