Renaming Main.java

In preparation for next...
Dropping inheritance in favor of composition.

@Mod classes will no longer inherit from ModBase ("is-a").
They will instead own a IModLifecycleManager instance ("has-a") if
needed.
Update README.md

This is much more than just "hey, these are dependencies I refactored
out of YALSM".  This is now shaping up to be the most significant part
of my mods.
So it deserves a README to introduce the concepts.