Add Webpack setup to the readme.md

[Vaccano]

The readme.md file only shows how to setup using JSPM.

It would be really nice to see how this should be setup for Webpack. (I get a breeze is not defined error.)

[Vaccano]

For those with this same error, adding this before my configure method in main.ts fixed it for me:

require('expose?breeze!breeze-client/breeze.debug');