Conversant Disruptor 1.2.11

[jo...@2ad.com]

Performance improvements for Java 8 and above.

Improved techniques to avoid cache line sharing
 - using @sun.misc.Contended in some key locations
 - -XX:-RestrictContended is now required for best performance

Initial Support for Java 9
- Provide a callback for handling PAUSE instruction in JVM
- onSpinWait is currently commented out for jdk8 build

Java 7 is no longer supported!

https://github.com/conversant/disruptor/tree/1.2.11