The handler was not returning `httpRunQuery`'s Promise, causing micro to send empty responses and leaving Node with unhandled Promise rejections when that Promise tried to write headers.
I also used `return` and `throw` instead of manipulating the response directly. This allows wrapping middleware to intercept responses if desired.
* micro is only supported in node 6 or greater
* update dependencies
* working Graphiql Server
* updated changelog
* fix linting errors
* adding micro to test suite
* added micro example
