Fix sort regex to respect sci-notated float number

closes #1145

As decribed in #1145, `.sort()` ignores floating numbers in scientific notation. 
For example `2.59e-10` [is treated as](http://jsfiddle.net/GpFhG/) `2.59` 

Failing spec: http://jsfiddle.net/LaLsd/
Fix provided by @enigmamf