bugfix: querytraversal should also work with mutations and subscriptions

add/fix javadoc

updated readme, delete readme.next

git ignore generated source folder

Merge pull request graphql-java#286 from dminkovsky/master

Updated README For v2.3.0

illegal global id should yield illegal argument exception

update reame to point to newest release 2.1.0

cleanup: reformat code and optimize imports

Merge pull request graphql-java#44 from henrikgs/master

Fix example for GraphQLUnionType

add source location and message to all validation errors