OPAL-2388: Removed the call to onCrossVariable when a variable is selected for contingency table
(cherry picked from commit 8066963)
OPAL-2387: Added a clear button that clears selected variables and contingency table
(cherry picked from commit 02ed628)
Cherry pick from contingency table improvements
Merge pull request #509 from emorency/contingency-submit-error-clear

Contingency table page improvements