Move away from single core functions, switch to decorators across method calls that better explain what the method is doing

[breck7]

In grammar langs we have execute methods.

But then the problem is execute is not a very helpful name.

In fact, it's a pretty terrible name.

So we should have a decorator command function strategy. So instead of a Stamp file node having an execute method, it should have something like a touchFileCommand. Generic code paths that now look for a single execute method recursively should instead look for the first Command function and call that.

This way, when I return to a language a few years later, I'll be able to know what a function does by reading the name, and won't have to wonder "wtf does execute mean for a file node?"

[breck7]

related: https://github.com/publicdomaincompany/jtree/issues/137

[breck7]

Just doing this gradually as we go.