implementation change

changed implementation of bytesToUUID and uuidToBytes to use big endian
format and to utilize ByteBuffer
Tests added
new test added

added test to guarantee representation is in correct format
tests cleaned up and code modified

Tests have been changed to utilize assertEquals and assertArrayEquals
cacheToValue now uses uuidToBytes
valueToCache changed

changed valueToCache to use bytesToUUID
merge JerettS: GUID byte representation change

Merge pull request #1427 from JerettS/sql-layer/AKGuidEndian-Fix
https://github.com/FoundationDB/sql-layer/pull/1427