Merge branch 'filter-submodules'

* filter-submodules:
  Update package.json, add tests and usage examples
  Incorporate changes from ben, update grunt-run-task
  Fixed typo.
  Switched to using options instead of top level config. Use { options: { filter: 'filter string' } } now. Also modified way grunt fork is called so that we correctly use subdirectory as working directory since prior method caused some modules to build incorrectly.
  Added filter option to allow filtering of submodules using config.

Conflicts:
	package.json