…er and appropriate handling of plaintext output during decryption prior to authentication.

…ers and make all implementations consistent.

Modified buffering in EAXBlockCipher to blockSize + macLength (instead of blockSize * 2) to align it with the OCB/GCM/CCM implementations and its own update-output size calculations (which often overestimated by a block size).
As a side-effect this reduces data copying a bit.

…ngthException in AEAD ciphers.

… and beef up testing.

Buffer underflows could occur when:
- decrypting data > internal buffer size in output stream (input stream was fixed in prior commit)
- packet mode AE cipher (e.g. CCM) is used with a data size > internal buffer size (since all output is buffered)

Buffer is now sized appropriately to every cipher operation immediately prior to it (using getUpdateOutputSize/getOutputSize as appropriate) in both streams.

Tests now run over boundaries of various block/buffer sizes to try to expose issues (0, 64 bit block, 128 bit block, 1K, 2K, 4K).