Standalone "Feet4Heels" 1.6

@sby was able to fix a long-standing issue with caused the skin to flicker when the mod was loaded through a character folder.
He also improved the compatibility with moreclothing.

This is merely a technical update, which allows other mods to discover if this mod is currently loaded.

The mod now maintains a marker variable indicating that it has been loaded.
loader.feet4heels_comm != null

The marker is removed upon mod unload.
loader.feet4heels_comm = null

The 1.1 version with nail polish has an error which prevents character code loading, and possibly causing other side effects.

Thanks to @tickles for spotting the bug and letting me know.

Version 1.2 fixes the problem.

Uses the color from the nail polish slider.