Remove Modernizr dependency

[sindresorhus]

No point in requiring Modernizr for so little code.

Had to wrap it in an IIFE, so not to expose the localStorage test.

Append ?w=1 to see the real changes.

[paulirish]

Because the localstorage is so much tricker than everyone expected, i'm prone to just let this continue to defer to modernizr.

it's repo is the source of truth on best-in-class detects and I dont want to maintain detects downstream here too.

[sindresorhus]

Sure, though, it's not like the test will change and it's like 5 lines, but ok. I can just use my fork.

[paulirish]

Well the test has changed at least 3 times since it landed in Modernizr: https://gist.github.com/paulirish/5558557

I don't trust any feature test to not change. The try/catch is kind of the
nuclear option, and we had to do it in this case. :/