reporting: xrange & yrange
reporting: allow selection of series in table
reporting: check user input for table class
Changed the behaviour of @dynDate/eq.

Return zero if A and B have no common frequencies (previously an error was returned).
Added dynDates/eq method.
Added @dynDates/plus method.
Added @dynDates/isempty function.
Added @dynDates/intersect function.
Cosmetic change.
Fixed bug.
Added @dynDates/minus method.