Emblem and unlockable SOFTcoding! Emblems and unlockables are no longer predefined in the code and instead loaded from IWAD

* Create a normal skin, but replace the S_SKIN lump with an almost empty one named P_SKIN.
* Provide "name = existing skin name as one of the first line (comments allowed)
* Reset individual spritenames back to zero sprite2s (or one for SPR2_STND to prevent complete removal) via "reset = SPR2_****" statements.
* No support for changing skin properties that are non-visual at the moment, but I don't really feel like it's wise to have those changable with patch alone. (Hello, tons of "modern Sonic" wadfiles which just change vanilla Sonic's ability to CA_HOMINGTHOK!)
* Sprites patch over.

To see an example in action, look at <root>/toaster/smilespatch.wad.

(no actual SLOC changes)