Changes gro without any args to print the task summaries along with their name. This means loading each task and their dependencies which is fine for performance in this case; we're still only loading a single task when one is resolved.

• log summaries
• add --help to log the same info as running gro taskname --help, but for all tasks
• add gro help alias for gro --help
• figure out schema extension in user projects (see the gro-task-schemas branch of felt-server)