Added entities to mod

Added textures, entity classes, render classes and models for my
entities.
Added handlers for achievements

Added three handlers for crafting, smelting and pickup achievements.
Blocks overhaul

Changed the block handling class and added a new 'glass'-like block to
the mod.
Added Achievements

Added some achievements with a handler to the mod.
Name changes and deletes
Changed my block superclass
Cleanup - Mod class