Recursively require a modules based on a webpack require context.
##Usage:
const requireDir = require('webpack-requiredir');
const result = requireDir(require.context('./src/actions', true, /\.js$/))
# result will be a hash containing modules by name.
##Options:
objectToModify - if given then results will be appended to this object
exclude - array of modules names. if in this list they are excluded from the require.
functionToApply - if provided a function that will be ran on every module included.