Ignore IntelliJ idea project files and ignore java/out folder
Feature - Implement Java API for Comparator and Slice. Allows use of
either byte[] or DirectByteBuffer for accessing underlying data.
Add locking to comparator jni callback methods which must be thread-safe
Fix to memory dealocation when creating a slice from a byte buffer
Fix code style problems identified by lint
Tests for ComparatorOptions, Comparator and DirectComparator, and by
proxy we also exercise Slice and DirectSlice
Fix code review comments raised in https://reviews.facebook.net/D22779
Merge pull request #231 from adamretter/master

Java API for Comparator and Slice