Add missing.js test files that requires any files that currently does
not have any unit tests defined for them. This should hopefully make it
so that when unit tests are added for parts of these files the coverage
will increase instead of decreasing.
Note that this does not include CLI Tools/ as those are not testable.
Replace the instancedirectory variable with an Instance class that holds
the directory and has a .path() to get paths relative to the instance
directory.
Change the ugly global slaves object to be a member of the db object and
implement the items database as a separate integrety verifying class in
lib/database.