Made theory functions tail recursive in books/ihs/ihs-theories.lisp.  Changed license on books/data-structures/array1.lisp to 3-clause BSD,

Changed some theories in books/ihs/ihs-theories.lisp to be
tail-recursive, to avoid memory growing too large for ACL2(h) built on
Allegro CL.

Changed license on books/data-structures/array1.lisp to 3-clause BSD,
as arranged with copyright holder (apparently an oversight that this
didn't happen sooner; thanks to Jared Davis for pointing this out).