asn1/ecdsa: add prelimary asn1 tests for regression testing
asn1: adds asn1 implementation
asn1/ecdsa: switch to asn1.js

Removes [now] unusued ECDSA functions parseSig, parseSigCompact and
serializeSig.
message: isolate tests further, remove redundant tests

The signing process does not care about a pubKeyHash, and nor does it
care about the network version on a base58 address string.
What signing does do independently is whether the compact signature has
a compression flag or not.

Variables names were also cleaned up a bit.
message: now network agnostic
index: remove TransactionIn/Out
index: remove unused variable