Changelog for Groovy 2.1.0-rc-3

Bug

[GROOVY-5918] - JsonBuilder.toString() fails with StackOverflowError when using Expando
[GROOVY-5922] - CompileStatic: long loses type when bitwise OR applied to it
[GROOVY-5933] - @TypeChecked$TypeCheckingInfo is added to constructors
[GROOVY-5934] - java.lang.OutOfMemoryError through Iterator.collectEntries and others (part 1: handle collectEntries)