Update peerDependencies for webpack 2

[goerwin]

Webpack 2 beta has been out for a while and this loader works fine with it. Can we update the peerDependencies to:

"webpack": "^1.4.0 || ^2.1.0-beta"

[sompylasar]

👍 please?

[sompylasar]

It has even got a PR: #233

[aight8]

+1

[Silviu-Marian]

+1

[ljwagerfield]

+1

[frenic]

+1

[jhnns]

Shipped with 3.2.1