Removed 'push' as 'lit' does the same job.
Reduced initial dictionary into a more basic one that can be extended.

Moved \ and BYE out of the Primitive type class, they are not part of
core words.
The interpreter extends the basic dictionary with \ and BYE.
This was done to allow for more interpreter specific words to be added
without infecting Primitive.
Added EXECUTE to dictionary.
Added SOURCE-ID
Added >R, R> and R@
Added EVALUATE