Close #297 - per command help output
EmberApp specific helper for an upgradeable default brocfile.

Most if not all features should still be available
bring back validation
Merge pull request #396 from stefanpenner/maintainable-brocfile

EmberApp specific helper for an upgradeable default brocfile.
Merge pull request #376 from dlmccoy/update_help_functionality

Update the help functionality to get info for specific commands
Update CHANGELOG.md