process.lua(see extended description)

followings are not complished yet:
stdin, stdout, stderr:   need STREAM first.
env:   used a function process.getenv() instead of
getgid(), setgid(id), getuid(), setuid(id):   only on POSIX platforms.
version, versions:   do it later.
umask([mask]):  may use _mask(m) in C.

process.nextTick(cb) is already done, but not tested yet.
uv_lua.lua has been changed.