* lisp/ob-scheme.el (org-babel-scheme-eoe): for marking the end of
session-based evaluation
(org-babel-execute:scheme): now supports session-based evaluation
(org-babel-prep-session:scheme): now works and defines variables
(org-babel-scheme-initiate-session): now works using run-scheme from
cmuscheme
* Makefile (LISPF): adding ob-scheme.el to the makefile
* lisp/ob-scheme.el: very preliminary support for evaluating scheme
code blocks
* lisp/org.el (org-babel-load-languages): adding scheme