Made the process of Pickling more accurate. Foods must first be brined for 24 hours, then they can gain the effects of pickling.

Also created a Food class for Food helper methods so that TFC_Core doesn't grow because of food. All Food NBT properties should be accessed using some kind of helper method, and never directly in the NBT.
Also adjusted decay rates of the various preservation techniques, however work on this is still ongoing.
Fixed Year Length ratio causing an incorrect scaling of food decay. Longer eyars caused faster decay. Oops!