crypt key is now split into two keys
@ the supplied crypt key is now split into two keys where
  one is used to XOR the data and the other is used to
  diffuse/mix the data
changed structure of classes in client
@ changed the layer structure from a inheritance based one
  to a member based, so each layer stores a reference to
  the lower layer allowing more dynamic building of stacks
  during run-time or more flexibility.
@ layers now use a design like interfaces to verify what
  they export as methods

	SimpleFS class 			-> BasicFS interface
	ChunkPushPullSystem class	-> ChunkSystem interface
	Client				-> StandardClient interface