Linux 3.19 has NOT been released.
Summary:
1. Prominent features
2. Drivers and architectures
All the driver and architecture-specific changes can be found in the [http://kernelnewbies.org/Linux_3.19-DriversArch Linux_3.19-DriversArch page]
3. File systems
4. Memory management
5. Block
6. Core (various)
7. Cryptography
8. Security
9. Virtualization
10. Tracing & perf