Allow imports in submodules

Signed-off-by: Shea Levy <shea@shealevy.com>
Give unique keys to submodule components

I'm not wed to the outPath values I chose, other options are probably
valid there too. It would be nice if we could track which file each
merged value came from as well.

Signed-off-by: Shea Levy <shea@shealevy.com>
When printing submodule keys, print just the file name if known

Signed-off-by: Shea Levy <shea@shealevy.com>
Merge branch 'allow-imports-in-submodules' into upstream-master

This allows submodules to use the full power of the module system.

Signed-off-by: Shea Levy <shea@shealevy.com>