HDKeys: Modified to have immutable properties
Opcode: Modify from methods to be static, and an instance be immutable.
Opcode: JS-Beautify
Bump
Merge pull request #717 from braydonf/feature/hdkeys-immutable

HDKeys: Modified to have immutable properties
Merge pull request #720 from braydonf/feature/immutable-opcode

Opcode: Modify `from` methods to be static, and an instance be immutable.
Changed *Json to *JSON and returned an object so that methods can be called from other toJSON methods without the double-stringification issue.
Consistent names for utilities
Block: Change utility naming