updated GMaven, GMaven 2, and GMavenPlus info and added Gant and Gradle info
Merge pull request #525 from keeganwitt/master

added/updated GMaven, GMaven 2, GMavenPlus, Gant, and Gradle info
GROOVY-6626: Add a BigInteger.power(Biginteger) method
Merge pull request #527 from PascalSchumacher/GROOVY-6626

GROOVY-6626: Add a BigInteger.power(Biginteger) method
GROOVY-6626: Add a BigInteger.power(Biginteger) method

corrected @since
GROOVY-6618: fix several constructor delegation related vargs bugs, that where also affecting enums
GROOVY-7134: Add @SelfType annotation for traits
GROOVY-7134: Make sure "this" can be used in the context of a self type
GROOVY-7134: Add documentation for @SelfType
GROOVY-7134: Fix potential NPE and reorder tests for faster execution
GROOVY-7138: Fix super call from inside a closure when @CompileStatic is used
GROOVY-7133: Fix class literal expecting primitive types not to use redirect