v6.4.0 (minor API changes)

replace ABIJSON::parseFunction, parseEvent, and parseError with ABIJSON::parseABIObject;
add type inference to ABIJSON::parseABIObject;
add type inference to ABIObject::fromJson and fromJsonObject;
add type inference to SuperSerial::deserializeArray;
add method Function::fromJsonObject(JsonObject,MessageDigest);
rename RLPItem export methods;
add RLPItem methods copy(ByteBuffer) and copyData(ByteBuffer);
add RLPItem method copy(OutputStream);
remove Tuple::toList;
throw NoSuchElementException when Tuple.get would return null;
minor performance optimizations;

SHA-256 (headlong-6.4.0.jar): dbb6cdcc1594a4cf000e147e1ca904bc51b8a9e887001c6899ba18abade07caf