encryptStream nad decryptStream

Oooof! yes, it took tome, and i am not done yet. but wanted to show progress. i implemented encryptStream and decryptStream, changed the engine to AES (question: do you want, at some point, to make it a selection so that the user can make the engine choice? might be a compatibility/compliance issue) and tests for enc/dec and creating a key (seemed like a trivial test).

i want to consolidate most of the code in enc/dec, as it is pretty much identical other than init'ing crypto. but as said, i wanted to show ***some*** progress.