Removing buffers

The main and only change is: we don't use buffers anymore. We are using Typed Arrays instead. Please try helper-functions to convert your hex-strings to Uint8Array.

Updated crypto & works in browser

• Compiled library from the latest iroha-ed25519 https://github.com/hyperledger/iroha-ed25519/releases/tag/1.3.1
• Reduced library size
• Works in Browser now :)