changed the memory allocation of txdataF and beam_weigths

Beamforming is now only done when necessary. This patch is based on one from enhancement-10-harmony.

Some of them might not be correctly handled.
I put /* TODO: XXX */ where I didn't know if
the fix was correct.

fixes for precoding (turning off if nb_antennas_tx=1), configuration files, timing advance with 3/4 sampling on 20 MHz, logging in MAC

bugfix for DCCH2/SRB2 in eNB_scheduler_dlsch.c, demultiplexing SIMD alignment issue in ulsch_decoding.c, IF5 fronthaul modification in lte-enb.c

see issue #166

see issue #165

see issue #165