added setf diag function
saving state.
added extended euclid, and redefined arithmetic on (mod n)
added prod method.
added map-tensor! macro, removed old commented macros.
slicing defmacro clause: added type declaration to get rid of style-warnings. scal: added scaldreshape! : before check uses store-size instead of size now\.
added normalize!
got rid of style warning stemming from define-tensor-method. added another class between numeric and real-tensor.
merged integer.lisp back into numeric.lisp.