Move message conversion from Source to Parser

- The TCP/UDP source classes were handling the conversion
  of messages from utf8 binary to a string, this now handled by
  the parser
Add supported for notification encryption

- New class CyborgPassKey to decode encrypted messages
- The parser now accepts one passphrase that will be
  used to decrypt messages
- This requires QCA2, added cmake module to find it
  in cmake/FindQCA2.cmake
Fix default number of hashes for cipher keys

- When hashing a passkey to use as a cipher key,
  the default amount of hash runs should be 1, when
  the given argument is 0 or less, but the variable
  was not being defaulted to 1.
Return QString() instead of ""
Fix indentation from tabs to 4 spaces
Rename class CyborgPassKey to CyborgCoder
Fix warning messages for CyborgCoder

- Rephrase the numHahses warning message
- Added new warning when setting a passphrase - if the coder
  does not support the necessary algorithms
Add encode() method to cipher messages
Merge pull request #2 from equalsraf/tb-security

Add support for encrypted notifications in the parser