gave max-val on insert random a default value of 42
put guards around push-back, push-front where pointers of head and tail elements were updated before being overwritten.  Can't overwrite fields of a null element.
return the linked list from the random linked list testing function.
have to set both front and back pointers on the first insertion.
fixed a bug where nth-from-* wasn't returning the element.  Fixed an issues with remove-random-element's remove-arbitrary-element test-case where it might ask for an illegal index.