Implement new EIP-1193 API

Added

• The most recent EIP 1193 API (#30)
  • The method request
  • The events disconnect and message
• A global initialization event, ethereum#initialized, for
  asynchronous injection (#31)
• Helper methods for initializing the provider (#31)

Changed

• BREAKING: Use named instead of default exports (#31)
• BREAKING: MetaMaskInpage constructor now takes a connectionStream and an
  options object (#31)
• BREAKING: _metamask.sendBatch -> _metamask.requestBatch (#30)
• BREAKING: Revert send to match provider in v7.7.8 of metamask-extension (#29)
• The connect event now emits with a ProviderConnectInfo object per EIP 1193 (#30)
• Deprecated the send method (#30)
• Deprecated the events close, networkChanged, and notification, and
  added deprecation warnings for them (#30)
• Un-deprecated sendAsync (#29)

Fix faulty null checks

• Fix faulty null checks
• Update package(s)

Remove over-eager eth_accounts error

This release prevents the incorrect firing of an eth_accounts-related error ("accounts updated unexpectedly").

Convert module to class, bind class methods to instance

• Converts MetamaskInpageProvider to an ES2015 Class.
  • Minor version bump as this is breaking in legacy browsers.
• Bind class methods to the instance in constructor function, preventing them from being called in an unbound state.
  • Fixes [email protected] compatibility issues

Optional metadata sending; typecheck request.method

• Added boolean constructor argument to prevent sending of site metadata, for use in contexts other than desktop browsers
• Added typecheck for request.method in the error middleware; this will intercept requests before passing them off if they have an invalid method string