Finally got rid of the XPACKed core and managed to cross-compile
all core words, which greatly simplifies the bootstrapping process.

TODO: implement X['] so that I can remove those XCURRENT patterns.

This allows us to move words like ABORT" to xcomp-core, which is
I think the last roadblock before being able to unify all drivers
into a single xcomp layer.

The goal is to insert device drivers in between.

That makes it easier to write drivers that can be xcompiled.

This allows us to get rid of the (parse*) indirection.

The way is clear for complete stage1 bootstrapping on the RC2014
target!