Created the top-level supervisor.

Starts the registry of `chkrec_keeper`s as well as their supervisor.
If either process goes down (due to an abnormal reason), then both
are restarted.

Also updated the application resource file with the list of named
processes spawned by this application.
Disabled auto-import of functions from `erlang` module.
Added `chkrec_keeper_mon:watch/2` function.

Calls `erlang:monitor/2` to keep track of when a `chkrec_keeper`
process goes down. This is done so that subsequent calls to
`chkrec_keeper_mon:lookup/1` will return the new pid. However, the
calls to `chkrec_keeper_mon:watch/2` and `chkrec_keeper_mon:update/2`
still need to be integrated into the initialization phase of the
backup keeper (i.e. `chkrec_keeper:init/1`) so the new pid is
actually stored when the process is restarted.

Note that the entry to the backup keeper is never removed, but can
only be overwritten. A better approach may be to only change the state
to `down` if the process had exited abnormally, and remove the entry
otherwise. (We can do this since we are using a `transient` restart
strategy for the `chkrec_keeper`s.)