waiting 2sec for alert

(fix attempt for saucelabs problems with double-alert)
added retire.js grunt task

for checking *unwanted* vulnerabilities
(bug: retire:node fails from call stack size)
coupons added
coupon field wrapped in collapsible

might confuse some scanners :-)
v1.5.0
added coupon challenge and corresponding tests
e2e testing of coupon forgery
added twitter-link for coupons
Merge pull request #63 from bkimminich/develop

Added coupons