DoubleClick v51; Hyperlocal mapping

- Update DoubleClick protocol to v51
- Map User.gender/age from new UserDemographics data
- Decrypt and map HyperlocalSet to Geo.lat/lon
- DoubleClickCrypto reviews: Hyperlocal API; support empty data
More DoubleClickCrypto reviews

- Have separate encrypt/decrypt and encode/decode methods
- More improvements in size validations
Merge pull request #5 from opinali/master

DoulbleClick protocol v51, crypto and mapper improvements