Converted itoa and ltoa calls to ultoa.

src/sbbs3/bulkmail.cpp

src/sbbs3/chat.cpp

src/sbbs3/data.cpp

src/sbbs3/data_ovl.cpp

src/sbbs3/download.cpp

src/sbbs3/email.cpp

src/sbbs3/exec.cpp

src/sbbs3/fido.cpp

src/sbbs3/file.cpp

src/sbbs3/filedat.c

src/sbbs3/ftpsrvr.c

src/sbbs3/getnode.cpp

src/sbbs3/listfile.cpp

src/sbbs3/logout.cpp

src/sbbs3/netmail.cpp

src/sbbs3/postmsg.cpp

src/sbbs3/str.cpp

src/sbbs3/un_rep.cpp

src/sbbs3/userdat.c

src/sbbs3/writemsg.cpp