Graphql-subscriptions

- Ensure INIT is sent before SUBSCRIPTION_START even when client reconnects [PR 85](https://github.com/apollographql/subscriptions-transport-ws/pull/85)
- Allow data and errors in payload of SUBSCRIPTION_DATA [PR 84](https://github.com/apollographql/subscriptions-transport-ws/pull/84)
- Expose `index.js` as entrypoint for server/NodeJS application to allow NodeJS clients to use `SubscriptionClient` [PR 91](https://github.com/apollographql/subscriptions-transport-ws/pull/91)
- Fixed a bug with missing error message on `INIT_FAIL` message [88](https://github.com/apollographql/subscriptions-transport-ws/issues/88)

- Fixed a bug with `browser` declaration on package.json ([Issue 79](https://github.com/apollographql/subscriptions-transport-ws/issues/79))

- Updated dependencies versions
- Fixed typings issue with missing `index.d.ts` file. [PR 73](https://github.com/apollographql/subscriptions-transport-ws/pull/73)
- Transpiling client.js to target browsers using webpack. [PR 77](https://github.com/apollographql/subscriptions-transport-ws/pull/77)

- Only attempt reconnect on closed connection. Fixes [Issue 70](https://github.com/apollographql/subscriptions-transport-ws/issues/70)

- Updated `graphql-subscriptions0.3.0`.
- Added `addGraphQLSubscriptions` - use it to extend your network interface to work with `SubscriptionsClient` instance. [PR 64](https://github.com/apollographql/subscriptions-transport-ws/pull/64)
- Client now uses native WebSocket by default, and has optional field to provide another implementation (for NodeJS clients)[PR 53](https://github.com/apollographql/subscriptions-transport-ws/pull/53)
- Client now support INIT with custom object, so you can use if for authorization, or any other init params. [PR 53](https://github.com/apollographql/subscriptions-transport-ws/pull/53)
- Server and client are now separated with `browser` and `main` fields of `package.json`. [PR 53](https://github.com/apollographql/subscriptions-transport-ws/pull/53)
- Client exposes workflow events for connect, disconnect and reconnect. [PR 53](https://github.com/apollographql/subscriptions-transport-ws/pull/53)
- Server exposes new events: `onUnsubscribe`, `onSubscribe`, `onConnect` and `onDisconnect`. [PR 53](https://github.com/apollographql/subscriptions-transport-ws/pull/53)
- Use `ws` package on server side, and expose it's options from server constructor. [PR 53](https://github.com/apollographql/subscriptions-transport-ws/pull/53)

- Properly propagate return() and throw() through withFilter [PR 74](https://github.com/apollographql/graphql-subscriptions/pull/74)