Eliminate unnecessary isupper() check before tolower().

Remove other instance of _tolower

Avoid using the obsolete _tolower() macro.

rcsid[] and sccsid[] and copyright[] are essentially unmaintained (and
unmaintainable). these days, people use source. these id's do not provide
any benefit, and do hurt the small install media
(the 33,000 line diff is essentially mechanical)
ok with the idea millert, ok dms

Remove the advertising clause in the UCB license which Berkeley
rescinded 22 July 1999. Proofed by myself and Theo.

KNF [return(foo) -> return (foo)]. ok millert@

spell command from 4.4BSD, now freed by Caldera.
I have made some significant changes:
o spell no longer uses hashed files. The algorithm for generating
the hashed files breaks down for large files. Instead, I use the
same approach as look(1) and do binary searches of mmap(2)ed files
which has acceptable performance. A side effect of this is that
spell can now search multiple word lists.
o The spell binary has been renamed to "spellprog" so as to not conflict
with the spell shell script. This is consistent with other operating
systems.
o The putsuf() and putword() functions have been renamed to
trypref() and tryword() respectively for consistency with modern
versions and for general sanity.
o the spell front-end shell script has been completely rewritten
o The code has been ANSIfied and re-style(9)d

spell currently must be compiled with -fwriteable-strings to make
the -b option work. This should be fixed.