Add Leon's video

git-svn-id: svn://svn.code.sf.net/p/amforth/code/trunk@1462 fd1c0b69-5d68-47f5-910c-86182ebb6ecd
Move 2DUP into core

It is used often enough as the sequence OVER OVER.


git-svn-id: svn://svn.code.sf.net/p/amforth/code/trunk@1463 fd1c0b69-5d68-47f5-910c-86182ebb6ecd
Move 2DROP into core since it is used very often.

git-svn-id: svn://svn.code.sf.net/p/amforth/code/trunk@1464 fd1c0b69-5d68-47f5-910c-86182ebb6ecd
Merge branch 'hq'