* hashtab.c: Remove debugging variables (all_searches,
all_collisions, all_expansions). Delete
all_hash_table_collisions.
(create_hash_table, delete_hash_table, empty_hash_table,
find_hash_table_entry, remove_element_from_hash_table_entry,
clear_hash_table_slot, traverse_hash_table, hash_table_size,
hash_table_elements_number, hash_table_collisions): Rename to:
htab_create, htab_delete, htab_empty, htab_find_slot,
htab_remove_elt, htab_clear_slot, htab_traverse, htab_size,
htab_elements, htab_collisions.
(htab_find): New function, handles common case where you don't
plan to add or delete an entry.
(htab_expand): Don't create a whole new table, just a new
entry vector.
(htab_find_slot): Simplify logic.
* hashtab.h (hash_table_t): Rename to htab_t.
(struct hash_table): Rename to struct htab. Shorten element
names. Reorder elements by size.
(htab_hash, htab_eq, htab_trav): New typedefs for the callback
function pointers.
(hash_table_entry_t): Discard; just use void * for element
type.