make apropos ignore case so it's more useful for getting access to the documentation

i19 : apropos "sort"

o19 = {rsort, sort, sortColumns}

o19 : List

i20 : apropos "Sort"

o20 = {isSorted, Sort, SortStrategy}

o20 : List

This would involve adding IgnoreCase as an option to apropos, match, replace,
and regex.  The default would be true only for apropos.
In scclib.c it involves adding REG_ICASE to SYNTAX_FLAGS.

But it's hard, because we don't have a way for compiled functions to have
options.  So we need to make one, or insert a top level method.
