Adds the following edify functions:
mount unmount format show_progress delete delete_recursive
package_extract symlink set_perm set_perm_recursive
This set is enough to extract and install the system part of a (full)
OTA package.
Adds the updater binary that extracts an edify script from the OTA
package and then executes it. Minor changes to the edify core (adds a
sleep() builtin for debugging, adds "." to the set of characters that
can appear in an unquoted string).
