Ideas: API changes and additions

[braydonf]

Since many of these haven't been touched, moving to the new repository and consolidating for overview:

Transaction:

• add Transaction.getSending/ReceivingAddress() (https://github.com/bitpay/bitcore/issues/692)
• stardard g7 toBuffer/fromBuffer for input/output (https://github.com/bitpay/bitcore/issues/742)
• standardize Transaction.from (https://github.com/bitpay/bitcore/issues/1013)
• shorten transaction.inspect output (https://github.com/bitpay/bitcore/issues/1222)
• immutable transaction (https://github.com/bitpay/bitcore/issues/1224)
• add Transaction#allTo (https://github.com/bitpay/bitcore/issues/1234)
• sighash api (https://github.com/bitpay/bitcore/issues/1187)
• transaction's input's addSignature and getSignatures (https://github.com/bitpay/bitcore/issues/1105)
• sigtype/nhashtype from crypto.Signature and Transaction.Signature (https://github.com/bitpay/bitcore/issues/1283)
• Deserialize inputs into the correct subclasses when possible (https://github.com/bitpay/bitcore/issues/1156)

Unit/URI:

• add Unit.isValid method (https://github.com/bitpay/bitcore/issues/978)
• chaining for URI creation (https://github.com/bitpay/bitcore/issues/1197)
• Unit: "toX" methods should have a "string" version (https://github.com/bitpay/bitcore/issues/1238)
• make Unit fail if initialized with undefined (https://github.com/bitpay/bitcore/issues/1127)

Block:

• Block/BlockHeader API improve block.header.prevHash (https://github.com/bitpay/bitcore/issues/1329)

Crypto/Keys:

• refactor crypto.ECDSA with nicer interface (https://github.com/bitpay/bitcore/issues/885)
• create a superclass for HDPrivateKey and HDPublicKey (https://github.com/bitpay/bitcore/issues/1090)

Errors:

• modularize errors (https://github.com/bitpay/bitcore/issues/1257)
• expose a better base error class (https://github.com/bitpay/bitcore/issues/1177)
• make all transaction errors instances of bitcore.errors (https://github.com/bitpay/bitcore/issues/1178)
• Improve error message when attempting to spend a p2sh output without supplying public keys (https://github.com/bitpay/bitcore/issues/1198)

Misc:

• add Chain constructor (https://github.com/bitpay/bitcore/issues/1150)
• move opcode.js inside lib/script (https://github.com/bitpay/bitcore/issues/1206)

[gabmontes]

Hi team! Any update on this? I'm particularly looking for bitpay/bitcore#1156. Thanks!