v20.0.0-beta2 (beta1->beta2)

This release contains simplifications and refactors to prepare to pull v20 out of beta. This release does contain breaking changes from our previous beta1 release, so refer to this list or the new README documentation if you are having issues upgrading to beta2

Changes include:

• Inclusion of optional AbiProvider in Api constructor (allows passing of local abi's as opposed to retrieving them from the chain)
• Moved tests and setup for tests into their own directory
• Remove default export in index.js to enable tree shaking in the future
  import eosjs from 'eosjs' -> import * as eosjs from 'eosjs' or specify exactly which named imports you need
• Pulled interfaces into their own files and exported them separately
  not possible before -> import { ApiInterfaces, RpcInterfaces } from 'eosjs'
• Simplify JsonRpc class
  import { Rpc } from 'eosjs' -> import { JsonRpc } from 'eosjs'
new Rpc.JsonRpc() -> new JsonRpc()
• clarify danger of bringing keys into webpage context by prepending signature provider export with Js
  import { SignatureProvider } from 'eosjs' -> import { JsSignatureProvider } from 'eosjs'
new SignatureProvider() -> new JsSignatureProvider()
• Export RpcError
• Changed BinaryAbi interface account_name field to camel case
• Updated README.md with new syntax and additional information
• set alwaysStrict flag in TSC
• Overall code cleanup