Added inline functions for w=4, 8 and 16.  Plus gf_inline_time.c to time the inline functions.  I see that gf_unit at present is not testing division -- that's a problem which we need to fix.
Added inline functions for w=4, 8 and 16.  Plus gf_inline_time.c to time
the inline functions.  I see that gf_unit at present is not testing division --
that's a problem which we need to fix.

Multiplication for w=4 & 8 is a little less than 2x faster when inlined.
w=16 is quite a bit slower.  If I had the patience, I'd test logzero inlined,
but I don't really have the patience at present.

imp/gf-complete,ceph/gf-complete,zzxuanyuan/gf-complete,cedricde/gf-complete,ceph/gf-complete,ceph/gf-complete,cedricde/gf-complete,imp/gf-complete,zzxuanyuan/gf-complete