quadgk.m: Overhaul function to add new "ArrayValued" option (bug #62468) * quadgk.m: Add "ArrayValued" option to docstring. Re-phrase bits of existing documentation for clarity. Rename input validation variable "str" to "prop" for clarity. Add decode for "arrayvalued" property. If limits of integration are high to low then reverse them in function rather than recursively calling quadgk(). Add FIXME note about missing input validation for several properties. Delete variable 'h0' which was never used. New code branch if "ArrayValued" is true which uses same code strategy as for normal quadgk, but subfunction __quadgk_eval_array__ for evaluating the function in a vectorized manner. Add BIST tests for "ArrayValued" input. * quadgk.m (__quadgk_eval__): Eliminate "too_close" output and code to calculate "too_close" which was never used. * quadgk.m (__quadgk_eval_array__): New subfunction.