Pull in patches from Zepto.js

https://github.com/madrobby/zepto/commit/f4bbec869d0a5d25289db3ec1364c468da5f73a1

https://github.com/madrobby/zepto/commit/524ee26cb5d19894366cfffb0a9f5e3841359b5b

https://github.com/madrobby/zepto/commit/8d6dd61f95f7950f00d4c19b0accfb4f32989f1f