Add KDF to supported algorithms in README.
Add AES256 / SHA384 to ECIESParam list.
Update and move ASN.1 code.

--HG--
rename : asn1.go => ecasn1/asn1.go
sorting out some bits in the ASN.1 section
Add GEC 2 to references, note NIST-compliance goal.
Updating ASN.1 definitions.