add doc string for strhash_iter()
add doc string for strhash_add()
add doc string for strlist_free()
add doc string for strlist_pushback()
add doc string for strhash_resize()
add doc string for mem()
add doc string for strhash_free()
add doc string for strhash_hash()
add doc string for strhash_new()
don't doc string if there is nothing interesting
implement str_len()
use str_len() instead of strlen()
adjust for str_len()