do not doubly try/catch inside work.js
trust selfPeer in client/account tests
do not create a full Session instance inside work.unravelAccount. fixes #260
handle errors inside Session.create that may occur when adding chunks to the transaction
fix memory leak in diary
XOR ASCII codes rather than characters at string indices in constEqual. fixes #261
readd signature to addContainerSessionKey chunk in session.create and abort the transaction when one of the chunks errs
extract plaintext from encryptAndSigned keys in work.unravelAccount
clean up encryptAndSign integration tests