Update ClassLoaderFixer to v2

[ThexXTURBOXx]

Today I released ClassLoaderFixer 2. Most changes here are not really necessary, but I still applied some of them to be consistent :) By the way, this exact same class also works for every version up to 1.4.5 - so feel free to incorporate it in every version up until then. At least public static String FIXER_VERSION = "2"; would be important to add everywhere to tell Block Helper to shut up (otherwise it warns the user everytime that he needs a proper RelaunchClassLoader implementation - even though it is indeed fine)