Support add function as user script.
Remove contiguous argument restriction from user scripts.
Add add_dir and remove_dir scripts.
Add add_vm script and support for vm_file.

A vm_file is essentially a host_file with the level data embedded directly in
the current level data. My intention is to make these encrypted also, so
that they are in effect a combo of an encrypted directory and a host_file.
Add encrypt script.
Add push and pull scripts.
Correctly set offset for created directories.