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'
iOS demo subscribe add pre condition
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
Update README.md

reformatting README
Update README.md

README edit
Completed Asana tasks:
* 4295160797797 - partially, there is misleading message from analyzer on
  one of functions