Created mrpropper task to hard clean before commit
Created mrpropper task to hard clean before commit

Grunt task mrpropper cleans directory structure from data which
should not be commited into repository.

MaxKarel/engine,peterkacinec/engine,tomatell/engine,peterkacinec/engine,MaxKarel/engine,MaxKarel/engine,sosik/registries,peterkacinec/engine,tomatell/engine,peterkacinec/registries,sosik/registries,sosik/registries,peterkacinec/registries,peterkacinec/registries,tomatell/engine