Major Refactorization

I did a major refactoring of both the code and the repo.
Changes:
Moved Block initialization and registration into AlexBlockLoader.
Moved Item initialization and registration into AlexItemLoader.
Moved Crafting Recipe Registration into AlexCraftingManager.
Replaced .class files with .java files (most eclipses don't work with
.class files, so I changed it to .java for compatibility).
Removed the .jar file (the .jar file has to be a seperate download, not
in the repo).