implemented SHA and ASCII HEX codes to generate key for AES256
experimenting with encryption
Encryption:
* implemented methods for encryption/decryption
* Crypto helper class should be updated a bit to support multithread
  or simultaneous calls
* place crypto helper calls into message send/receive cycles
Completed Asana tasks:
* CL-3777612898118
Merge branch 'master' into encryption
merged with master
adding new gitignore
adding workspace file
Merge branch 'encryption'
Removed Xcode warning on CryptoHelper
Comleted Asana tasks:
* CL-3777612898118
Merge branch 'encryption' of https://github.com/pubnub/objective-c
message.message is DECRYPTION_ERROR is encryption is on
Merge branch 'encryption'
xcode files
Merge branch 'master' of https://github.com/pubnub/objective-c