Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Port top to the alpha.

Submitted by: Hidetoshi Shimokawa <simokawa@sat.t.u-tokyo.ac.jp>

This commit was generated by cvs2svn to compensate for changes in r24139,
which included commits to RCS files with non-trunk default branches.

This is the long-awaited import of top into the base system (actually,
the src/contrib/top part right now). This tools is simply too system-
dependant to maintain it in the ports collection.