Add documentation and examples (#145)

* Add documentation

* Justification u8a decoding and json encoding (#146)

* Decode Justifications

* Json encoding for justifications

* Bump deps

* Allow extrinsic length encoding to operate on u8a[] (#148)

* Fix config and move generated doc to a subfolder

* Cleanup extrinsic encoding (#150)

* Cleanup extrinsic encoding

* Removed now-defunct type

* Add uncheckedLength encoding

* Add examples

* Ignore package-lock since we use yarn

* Cleanup examples

* Add gitbook config and some base files for the doc

* Do not make full doc mandatory for now

* Add contributing guide, polish doc and samples

* Update the deps of all samples and add yarn scripts
Fix and regenerate the doc

* Fix Contributing guide

docs/api-provider/modules/wsprovider.eventemitter.md

@@ -0,0 +1,29 @@
+[Polkadot JS API](../README.md) > [WsProvider](../classes/wsprovider.md) > [EventEmitter](../modules/wsprovider.eventemitter.md)
+
+# Module: EventEmitter
+
+## Index
+
+### Interfaces
+
+* [EventEmitterStatic](../interfaces/wsprovider.eventemitter.eventemitterstatic.md)
+* [ListenerFn](../interfaces/wsprovider.eventemitter.listenerfn.md)
+
+### Variables
+
+* [EventEmitter](wsprovider.eventemitter.md#eventemitter)
+
+---
+
+## Variables
+
+<a id="eventemitter"></a>
+
+### `<Const>` EventEmitter
+
+**● EventEmitter**: *`EventEmitterStatic`*
+
+*Defined in /Users/will/projects/paritytech/polka/polkadot-js-api/node_modules/eventemitter3/index.d.ts:61*
+
+___
+