Draft: Merge of BLTSuperMod and BLTMod + tags system

• Removed BLTSuperMod class and moved its utility functions to the new Utils.IO class
• It is no longer mandatory to have a mod.txt in the mod folder nor is it mandatory to have a supermod.xml. This is done to allow anything in the mods folder that may not be specifically a BLT mod.
• A new "tag" system, similar to BeardLib's modules, but simpler. The idea of it is allowing mods (like BeardLib) to utilize it and allow for adding tags to supermod.xml or mod.txt. It also allows us to define the existing "tags" to automatically initialize on defined events without hardcoding them like we used to.
• New tag: scripts, similar to BeardLib's Classes, it allows modders to run scripts (dofile) without forcing them to define a global or anything. Scripts are loaded much earlier than hooks so they serve a big purpose of allowing you to also hack SBLT (like adding tags). You can also use them to define a class you may initialize later on.
• SimpleClbk to run a function callback without object reference.
• ClassClbk to run a callback in an object/class.
• ToBoolean to convert string value to boolean (strict & useful for XML).

Closes #47

TODO: test, test, test!