Add parser step. Can now nest quotes.
Add a basic REPL
Uncomment test.
Add dup function.
Add pop function.
Add swap function.
Add clear function.
Add true and false.
Refactor tests.
Add if function.
Add eq function.
Add quote function.
Add dip function.
Add def function. Fix parsing of quotes to maintain order.
Obey RPN convention for operand ordering. (i.e. '1 2 -' equals -1 not 1)
Add lt, gt, leq, geq functions.
Convert test use yaftTest helper.
Whitespace tidying.
Quote strings consistently
dup-ed quotes are independent of the original.