License wording

I noticed that the paragraph of text at the bottom of the license still referred to the "REGENTS" although there is no mention of it anywhere else in the license. Seems like a typo that should read "COPYRIGHT HOLDERS". I made the change in two commits: one changing the word, the other changing the formatting, so it would be easier to see what was changing.

The original copyright on BSD software was held by the Regents of the University of California, which is likely the source of this text.  See for example
 
http://www.openbsd.org/cgi-bin/cvsweb/src/bin/cp/cp.c?rev=1.35

Anyway, since there is no longer any regents involved, I thought it best to change the wording.

See also http://opensource.org/licenses/BSD-3-Clause for some commentary on the wording.