Allow for multiple plugin results

# Feature Request

## Motivation Behind Feature

This feature is present on the other platforms and it makes sense to be able to send multiple results, for example when opening a socket and passing the incoming data on to the web window

I have created an implementation for this feature, please see this [pull request](https://github.com/apache/cordova-electron/pull/247)

Review the implementation referenced in pull request #247 and compare it with the existing plugin-result handling. Confirm how multiple results should be delivered for cases such as socket data passed to the web window, then verify that the behavior is covered before considering the feature complete.

Written by the indexing model from the issue text.