fixes needed before we can use submodules

[masinter]

I had hoped to convert the medley/fonts directory to a separate repository using the git "submodule" feature.

The submodule feature allows you to say that a directory in the main repo (Interlisp/medley) is actually it's own repository which can be updated independently, with different license, checkout or merge rules, owners.

Ultimately, we should consider making other Interlisp repos into submodules of medley:

• loops
• notecards
• test
• maiko (!)

A few things need to change before we can do this:

• GITFNS at least needs an update (and possibly other places) to ignore the .git directory of the submodules.
• THe loadup scripts that checkout medley should use the right flags to checkout the master branch of the submodules by using the --recurse-submodules flag to the checkout command, and to allow the directory to be a subdirectory of medley rather than an aunt (sibling of a parent).