Eval-sexp-fu and Emacs 24-26 support

When the eval-sexp-fu packages is loaded, it will flash the last sexp evaluated within a buffer.
Also, added Emacs 26 function so package is compatible with Emacs 24-26.

Fast Interactive Emacs Lisp Evaluation

This is the first public release of rsw-elisp.el to improve your interactive Emacs Lisp experience.