add option displayModemDebugMessages to optionally disable or enable debug log messages coming *from* the modem; properly check if we're operating in DFSI or not and if we are do not attempt to set the FIFO buffer lengths or clear buffers related to DMR or NXDN; correct deletion of array types in the DFSICallData structure; correct bad length of the VHDR1 during DFSICallData initialization, the length defaulted to TIA mode which would cause a crash when trying to delete and deallocate VHDR1 when used in V.24 mode;