Extended the REPL to print out expression value

[olwmc]

The REPL now prints out the value, if available, of any expression entered.

Examples:

> 1+2
3
> let x = 5.
> x == 6
False
> x == 5
True
> x == 11 or 1 == 1.
True.
> function foo 
.    with x:%string do
.        "Altered " + x.
.    end
> foo("asteroid").
Altered asteroid
> foo("string") + " !"
Altered string !

[olwmc]

Need to fix something quickly

[lutzhamel]

Nice!