Adjustments for sbcl 1.3

[mmaul]

plot-window was failing due to error generated by read-delimited-list refusing to be used outside out side of a call to read when the parameter 'recursive-pwas not set to nil (Not sure at what point this became a problem, I suspect it was probably SBCL actually started enforcing therecursive-pparameter). I have submitted a pull request toedicl/cl-interpoland the required changes has been merged into 'edicl/cl-interpol master. Made some changes to README.md as flot-example-1 needed to be called before plot to set up the target element, added instructions for getting modified cl-interpol and reworded a few things.