Add Helen to waiting list

waitinglist.rst

@@ -15,3 +15,4 @@ based on the order of this list):
 * Chris Foresman - Chicago, IL USA. [email protected]. Senior Systems Engineer, Vokal; Python Programming Instructor, Northwestern University Center for Talent Development
 * Angus Thomas - Horsham, UK. [email protected] Code Club leader
 * Joshua Jay herman - Chicago, IL [email protected] Member of chipy and CEO of A Cons Apart developing software for 3d printing and search by shape.
+* Helen Sherwood-Taylor - Haslemere, UK - Freelance developer and pythonaut, keen to spend some time with the microbit :)