Tue Jun 14 10:23:51 2005  George Lebl <jirka@5z.com>

	* src/symbolic.[ch], src/eval.[ch]: Add a primitive
	  SymbolicDerivative function.  Doesn't yet even get even all the
	  simple cases (such as functions with more then one argument) but
	  should be semi usable for simple things.  Of course there is no
	  simplification of expressions in genius so things can get wild a
	  bit.

	* src/graphing.c, src/funclib.c: adjustments because of the above

	* src/calc.c: remove an extra parenthesis in function printing
	  output.

	* src/geniustests.txt: add tests for SymbolicDerivative

	* help/C/gel-function-list.xml: Add SymbolicDerivative blurb