Change back get-t3-for-signing to use JSON instead of QS
Add add_contract_outcome/2
Correct hybrid AES/RSA encryption

* Change RSA key size generated in JS in prep page to 2048.
* Remove RSA privkey passphrase encryption from JS generated key.
* Correct binary syntax of final length of sub binaries in AES/RSA
  encryption function.
* Add decryption test using generated test data.
* Update comments and reduce number of demo contracts.
merge of ready-for-bj with master