dvisampler/chansync: use Record.raw_bits()
microudp.c: avoid redundant accesses into multi-level structures
tftp.c: use symbolic constants for protocol opcodes
tftp.c (rx_callback): simplify expressions containing unnecessary casts
tftp.c: make "packet_data" unsigned and optimize strcpy+strlen
tftp.h, tftp.c (tftp_get): make "buffer" void and use unsigned char internally
tftp.c: use uintNN_t instead of "unsigned short", etc.
tftp.c (format_request): pass opcode as argument
tftp.c: use symbolic constant for block size
tftp.h, tftp.c: add tftp_put