Added adaptive CMA equalizer, "fixed" CD and phase noise

Added adaptive CMA equalizer, "fixed" CD and phase noise

Implemented CMA equalizer. It can be seen that it works well
in equalizing the received signal when CD is small (i.e. when
the CD compensation does not work well). Convergence is to be
discussed.

Previous version of CD fails miserably when CD is small but
compensation is not used. This is due to the constellation being
rotated by the CD simulation. Code was added to rotate it back.

Previous version of phase noise has a lot of errors due to
cycle slips when attempting to recover the phase using the
Viterbi-Viterbi algorithm. Experimenting with different block
sizes did not help much. A differential PSK was attempted which
seems to work well, agreeing with supervisor's predictions on
asymptotic behaviour, though incurring a penalty at lower SNRs.