v6.2.0 - Modular Structure / Updated Keccak

This release comes with a new file structure, related functionality is now broken down into separate files (like account.js) allowing for more oversight and modular integration. All functionality is additionally exposed through an aggregating index.js file, so this version remains backwards-compatible.

Overview on the new structure:

• account: Private/public key and address-related functionality (creation, validation, conversion)
• byte: Byte-related helper and conversion functions
• constants: Exposed constants (e.g. KECCAK256_NULL_S for the string representation of the Keccak-256 hash of null)
• hash: Hash functions
• object: Helper function for creating a binary object (DEPRECATED)
• signature: Signing, signature validation, conversion, recovery

See associated PRs #182 and #179.

Features

• account: Added EIP-1191 address checksum algorithm support for toChecksumAddress(),
  PR #204

Bug Fixes

• bytes: toBuffer() conversion function now throws if strings aren't 0x-prefixed hex values making the behavior of toBuffer() more predictable respectively less error-prone (you might generally want to check cases in your code where you eventually allowed non-0x-prefixed input before), PR #197

Dependencies / Environment

• Dropped Node 6, added Node 11 and 12 to officially supported Node versions,
  PR #207
• Dropped safe-buffer dependency,
  PR #182
• Updated rlp dependency from v2.0.0 to v2.2.3 (TypeScript improvements
  for RLP hash functionality),
  PR #187
• Made @types/bn.js a dependency instead of a devDependency,
  PR #205
• Updated keccak256 dependency from v1.4.0 to v2.0.0, PR #168