* Invoke subgraph handler in watcher event processing
* Fix error when invoking subgraph handler
* Parse events using event signature specified in subgraph yaml
* Use contract abi to parse event params
* Invoke event handler based on event signature
* Fill event with block and transaction data
* Comment missing fields in block and transaction data
* Invoke handlers based on watcher-ts events
* Read subgraph yaml and listen to events from watcher-ts
* Create GraphWatcher class to use in generated example contract watcher
* Call graph-node event handler from generated watcher
