UBIFS File System - Make File System program

* crc16.h and crc16.c were copied from the linux kernel.
* crc32.h and crc32.c were copied from mtd-utils and amended.
* ubifs.h is a selection of definitions from fs/ubifs/ubifs.h from the linux kernel.
* key.h is copied from fs/ubifs/key.h from the linux kernel.
* defs.h is a bunch of definitions to smooth things over.
* lpt.c is a selection of functions copied from fs/ubifs/lpt.c from the linux kernel, and amended.
* hashtable/* was downloaded from http://www.cl.cam.ac.uk/~cwc22/hashtable/
