Add gulp as grunt alternative in example project.

See README in the gulp-able directory for usage instructions.
Merge branch 'gulp-able' of https://github.com/mkelley33/mean into mkelley33-gulp-able

* 'gulp-able' of https://github.com/mkelley33/mean:
  Add gulp as grunt alternative in example project.
reorganize for grunt/gulp

added tools directory
anticipate building out for sass/less support