minor list cleanup

This patch makes a few minor cleanups:

(1) Replace while loop with the new forboth() construct in
parser/analyze.c

(2) Replace lcons() with lappend() in SearchCatCacheList(). Since these
now have the same performance, there is no reason to prefer lcons() in
this case, and using lappend() leads to cleaner code.

(3) Improve the name of the second parameter to for_each_cell()

Barring any objections, I intend to apply this patch later today.

-Neil