fix(component): reset the captcha when the component is destroyed
fix(component): reset the captcha when the component is destroyed

Ensure we get rid of all recaptcha leftovers when the component is no longer needed; fixes #10
DethAriel/ng-recaptcha,DethAriel/ng-recaptcha,DethAriel/ng-recaptcha,DethAriel/ng-recaptcha,DethAriel/ng2-recaptcha