* PubSub Integration WebSocket
* PubSub Provider API
* Parity License and fix switch statement
* Minor fix: use parameter api
* Exclude subscriptionId return
* Unsubscribe parameters as array
* secureProvider API added
* isSecure check
* Refractor: Formatting in callback (no Promise)
* Tests for parityProvider
* Refractor: Formatting in callback (secure API)
* Updated transaction documentation
* Module instead of API-Names, Options always as array (e.g. empty)
'parity' instead of 'parity_subscribe' calls
params with empty array as options. If eth_subscribe includes empty array parity-core will send invalid request (eth api doesn't have options)
* Removed isSecure transport check, because APIs are configurable
* Refractor Provider API to single Pubsub
* Modify transport layer to have single identifier for subscriptions
* FIX: Display pubsub errors
* Discard Messages after unsubscribing
* Fix: display error normal messages correctly
* Simplified code, removed unnecessary pubsub methods
* trace_call API 2nd argument blockNumber, first whatTrace
https://github.com/paritytech/parity/wiki/JSONRPC-trace-module#trace_call
* Separate namespaces pubsub. eth, parity, net
* Keep error for messages from unsubscribed topics.
* Fix: Unsubscribe Promise
* Add Test: Unsubscribe promise resolved
* Fix: 'error' in params
