paths accepts function that returns paths
Merge pull request #153 from ananthakumaran/paths-function

Paths accepts function that returns paths
Path function option update
Updated the docs for `paths` option

The docs now say more about passing a function for the value of paths.
remove grunt-lib-contrib - fixes #156

Also remove the `report: false` choice in a backwards-compatible manner. It's really moot.
Remove deprecated grunt.util.*

Instead, use lodash module and async module
Merge pull request #158 from shinnn/master

Remove deprecated grunt.util._ and grunt.util.async
Allow custom functions return types defined within less

More generic type checking for custom function return