Merge pull request #139 from lmle/feat/client/ab_test

(feat) ab_test: send millisecondsAfterStart to server
(feat) Remove minified CSS from gitignore
Merge pull request #140 from darabun/master

(feat) Remove minified CSS from gitignore
(feat) Add process.env.NODE_ENV to handle different directives when deployment
Merge pull request #141 from nrobeR/master

(feat) Add process.env.NODE_ENV to handle different directives when deploying
(feat) ab_test: Send millisecondsPickWinner and millisecondsStartTime to server