Graphql-subscriptions

- Fix for first subscription is never unsubscribed [PR 179](https://github.com/apollographql/subscriptions-transport-ws/pull/179)

- Increase default keep-alive timeout to 30s [PR 177](https://github.com/apollographql/subscriptions-transport-ws/pull/177)
- Operation key is now `string` instead of `number` [PR 176](https://github.com/apollographql/subscriptions-transport-ws/pull/176)

- Fix for reconnect after manual close [PR 164](https://github.com/apollographql/subscriptions-transport-ws/pull/164)
- test(disconnect): added tests for client-server flow for unsubscribe and disconnect [PR 163](https://github.com/apollographql/subscriptions-transport-ws/pull/163)
- Various dependencies updates [PR 152](https://github.com/apollographql/subscriptions-transport-ws/pull/152) [PR 162](https://github.com/apollographql/subscriptions-transport-ws/pull/162)
- docs(README): fix docs [PR 151](https://github.com/apollographql/subscriptions-transport-ws/pull/151)

- Client exposes new asyncronous middleware to modify `OperationOptions` [PR 78](https://github.com/apollographql/subscriptions-transport-ws/pull/78)
- Added `WebSocketServer` error handler to prevent uncaught exceptions. Fixes [Issue 94](https://github.com/apollographql/subscriptions-transport-ws/issues/94)
- Updated `ws` dependency to the lastest.
- Introduce lazy mode for connection, and accept function as `connectionParams` [PR 131](https://github.com/apollographql/subscriptions-transport-ws/pull/131)
- Extend transport protocol to support GraphQL queries and mutations over WebSocket [PR 108](https://github.com/apollographql/subscriptions-transport-ws/pull/108)
- Added built-in support for `subscribe` from `graphql-js` [PR 133](https://github.com/apollographql/subscriptions-transport-ws/pull/133)
- Fixed infinity reconnects when server accepts connections but its in an error state. [PR 135](https://github.com/apollographql/subscriptions-transport-ws/pull/135)
- Force close client-side socket when using `close()`, and ignore reconnect logic. [PR 137](https://github.com/apollographql/subscriptions-transport-ws/pull/137)
- Added new connection events to give a more accurate control over the connection state [PR 139](https://github.com/apollographql/subscriptions-transport-ws/pull/139). Fixes [Issue 136](https://github.com/apollographql/subscriptions-transport-ws/issues/136).
- Replaced `Object.assign` by `lodash.assign` to extend browser support [PR 144](https://github.com/apollographql/subscriptions-transport-ws/pull/144). Fixes [Issue 141](https://github.com/apollographql/subscriptions-transport-ws/issues/141)

- Protocol update to support queries, mutations and also subscriptions. [PR 108](https://github.com/apollographql/subscriptions-transport-ws/pull/108)
- Added support in the server for GraphQL Executor. [PR 108](https://github.com/apollographql/subscriptions-transport-ws/pull/108)
- Added support in the server executor for `graphql-js subscribe`. [PR 846](https://github.com/graphql/graphql-js/pull/846)

- Remove dependency on `graphql-tag/printer` per [graphql-tag54](https://github.com/apollographql/graphql-tag/issues/54) [PR 98](https://github.com/apollographql/subscriptions-transport-ws/pull/98)