BUGFIX: deny mode, tmp lock, byte lock when length is -1, setforkparams,

BUGFIX: deny mode, tmp lock, byte lock when length is -1, setforkparams,
AFP3 large file support

deny mode: make it works with more than 2 openers

tmp lock: check conflicting locks with files open multiple times by the same
process, was only check locks held by other afpd.

byte lock: -1 means to the maximum size of a fork, was always error EOVERFLOW,
because we don't start from offset 0 and we can't use the POSIX way ie length 0.

setforparams: only conflicting locks if it's a truncate and it removes a locked
range, was any lock return an error.

AFP3: check for negative values with 32 bits calls, setforparams for size >2GBytes,
read and write with offset > 2GBytes.