PHP: Extend unit tests to check symmetric ciphers block size.
Lib: Add methods to deremine symmetric ciphers current mode: encryption or decryption.
Lib & PHP: Rename class VirgilMultipartCipher to the class VirgilChunkCipher. Add additional methods that allows adjust size of chunks. Add correspond unit tests.
AS3: Add wrapper for the class VirgilChunkCipher.