Cleanup of simple-cache.c. (Bug 172). Allocate less memory when

performing a pattern name match.  
* src/server/simple-cache.c: Removed obsolete comments.  Fixed
spelling errors in comments.
(find_matching_info_compare): Don't overflow if a Conf_no doesn't
fit in an int.
(find_matching_info): Removed obsolete comments (bug 172).
(rebuild_matching_info_entry): Added a comment that explains a
magic "2" in the code.
(build_matching_info): Use cached_no_of_existing_conferences()
instead of next_free_num when deciding how large temporary table
we need.  Reduce the number of loop induction variables.
(cached_lookup_name): Made code more readable by introducing a
temporary variable.