Prepare for deploying

http://stackoverflow.com/a/5190323/3289396

Squashed commit of the following:

commit ef62e9a7479cdcb2ca20ce7d31c2cd97b231eedb
Author: pdostal <git@pdostal.cz>
Date:   Sun Oct 12 15:54:03 2014 +0200

    Remove execjs

commit 495bb70a4a3807ac8d11aee9771edb0987365d29
Author: pdostal <git@pdostal.cz>
Date:   Sun Oct 12 15:48:22 2014 +0200

    Remove duplicate therubyracer

commit 142bcf33d9e2c7677a0d2a424242faca93e2604d
Author: pdostal <git@pdostal.cz>
Date:   Sun Oct 12 15:43:47 2014 +0200

    Temporary disable some tests

commit d0390685311cbafe60da3a22582fae5a6c5f1012
Author: pdostal <git@pdostal.cz>
Date:   Sun Oct 12 15:34:26 2014 +0200

    Add CodeShip badge to README.md

commit 4ff7ab2e9cc9e7b48353dd6e64e3001a16d368fd
Author: pdostal <git@pdostal.cz>
Date:   Sun Oct 12 15:10:19 2014 +0200

    Fix js problem