Several large refactorings

* Refactor location of all data files to include a subdirectory
  for the mod version
* Update the BaseModel class to allow models to load themselves from
  any text file (whether JSON or CG)
* Refactor ModPack & ModVersion to move the laoding functionality in
  one into the other (and use the new stuff in BaseModel)
* Move the parser versions into a new subdirectory which allows for
  future additional parsers

src/data/buildcraft/6.2.6/mod-version.cg

@@ -1,5 +1,5 @@
 schema: 2
-name: BuildCraft
+name: Buildcraft
 version: 6.2.6
 description: Crafting recipes from BuildCraft, by SpaceToad