Removed the use of b.array() to support DirectBuffers. Removed Table extend Constants.
Revert "Removed the use of b.array() to support DirectBuffers. Removed Table extend Constants."

This reverts commit 9ed40b2b4b782f79ad7171b8cd3bb8c57756a61b.
Revert "Made FlatBufferBuilder.java require ByteBuffers that have an array."

This reverts commit 354aad4bc541c6a1346e8aac33fd3cdc9d951edb.