Added error categories for routing exceptions and altered rng to increase security.
Merge remote-tracking branch 'maidsafe/next' into MAID-328-consider-autoseededrng-use
Removed unused error codes for now
Merge pull request #48 from dirvine/MAID-328-consider-autoseededrng-use

Maid 328 consider autoseededrng use
Merge remote-tracking branch 'upstream/next' into MAID-369-refactor-routing