SuReal(surface realization) initial version

This is the a preliminary version of Surface-realizaion(SuReal). The main function is sureal which takes in a SetLink of relex-to-logic output to parrot/echo back the sentence.  Use (r2l "some sentence") rather than (reles-parse "some sentence") to get the SetLinks for testing purposes.
Maybe I did not understand, but .. you are getting back a string from relex, and that string is mostly scheme code, with some embedded comments.   So now you are going to scan that string, looking for those comments?  Seems awkward.
```
So, instead of writing
; ##### START OF R2L #####
f
g
h
; ##### END OF A PARSE #####
```
why not do this:
```
f
g
h
(define stuff-i-need f g h)
```
That way, you don't need to scan the string ...