nip06 package for key derivation.

rename Equal -> FilterEqual.

relay policies as interfaces, SimplePolicy as the most basic implemen…

…tation.

move everything to the same directory.

nip-01 update: everything as arrays on filters.

.Until filter attr and filter.Equal() function.

upgrade interfaces, add local filtering for subscriptions and some ot…

…her things I forgot. also a README with examples.

event kinds as int, not uint8.

event kinds as int, not uint8.

event kinds as int, not uint8.