added configuration file for lowband of SoDeRa

make changes to use the fronthaul configuration parameters - updates to rrh_gw.c and eNB_transport.c wrt to changes in openair0_device struct

increase maximum users in eNodeB to 16

some changes in logging for XFORMS and UL scheduling (activation in all subframes and retransmissions only via PHICH)

Work with virtual interfaces, you will have to set the eNB virtual interfaces up yourself (ifconfig ethx:y ipv4@ up)

handling of timing advance is improved. MAC retrieves timing advance from phy once prior to DL scheduling and clears the statistic in PHY. A timer for controlling the timing advance periodicity was introduced.