Added ChronicleMap persistence as an alternative to SQLite

[akumaburn]

I did recently add ChronicleMap (https://github.com/OpenHFT/Chronicle-Map) as a store to CQEngine and tested it successfully. It is license compatible with this project using the same type - Apache 2.0 license: https://github.com/OpenHFT/Chronicle-Map/blob/ea/LICENSE

Usage is like:

ChroniclePersistence<Community, String> diskPersistence = new ChroniclePersistence<>((SimpleAttribute<Community, String>) GUID_ATTRIB, new File("persist.dat"),String.class,Community.class,UUID.randomUUID().toString().length()+1,64 * 1024,1000000);

ConcurrentIndexedCollection<Community> communities = new ConcurrentIndexedCollection<>(diskPersistence);

[npgall]

This is very interesting, and something I would be interested in merging.

I am hoping soon to carve out some time to take a closer look.