rewrite regex

[arthurvr]

and extract it into its own module.

https://github.com/arthurvr/timeline-url/blob/master/app/scripts/sidebar.js#L4

[arthurvr]

Not gonna put it in its own module. I ❤️ one-line modules but it's kinda difficult to have browserify or whatever way to pull in npm modules in a chrome extension. I don't want to overcomplicate the whole build system.