Add word "recursive" to core forth

[Eszartek]

Since there are two ways of creating a recursive word, either by including the word "recursive" in the definition or using the word "recurse" as a placeholder for it's own name, both words should be included.

Specifically, the "recursive" word allows for recursion, but would disallow referencing a previous definition of the word currently being defined. Whereas "recurse" would allow you to mix references to previous (by using its actual name) and the current (using "recurse").