add pthread_rwlock to threadsafe-ify bucket access
add lots more debugging and make debugging threadsafe
mark verbose() and debug() as attribute(format(printf))
cast debug() args as appropriate
undup: fix off-by-one-pointer in bloom1 tests, and factor out i1+nbloom1 for clarity
undup: remove extra arg from hash debug
bloom_dump: fix thinko in bit-match computation