refactors pkcs1, 8, and 10, separating ASN.1 specs from DER encoding
refactors pkcs1, 8, and 10, separating ASN.1 specs from DER encoding

also adds pkcs1 RSA public key en/de-coding and tests

urbit/urbit,jfranklin9000/urbit,jfranklin9000/urbit,urbit/urbit,urbit/urbit,ngzax/urbit,jfranklin9000/urbit,urbit/urbit,belisarius222/arvo,urbit/urbit,urbit/urbit,ngzax/urbit,belisarius222/arvo,jfranklin9000/urbit,joemfb/arvo,ngzax/urbit,ngzax/urbit,urbit/urbit,jfranklin9000/urbit,ngzax/urbit,ngzax/urbit,jfranklin9000/urbit,jfranklin9000/urbit,ngzax/urbit,joemfb/arvo