ZPOOL_PROP_AUTOTRIM is part of Trim support added in zfs 0.8 (https://github.com/zfsonlinux/zfs/commit/1b939560be5c51deecf875af9dada9d094633bf7). Add it and prevents panic when pool is reloading its properties. Fixes #19
Remove "typedef unsigned long int rlim64_t" as rlim64_t is already defined in /usr/include/i386-linux-gnu/bits/resource.h on 32 bits.