The write-test-dbs script will create a small set of test databases with a
variety of data and record sizes (24, 28, & 32 bit).

These test databases are useful for testing code that reads MaxMind DB files.

There is also a `maps-with-pointers.raw` file. This contains the raw output of
the MaxMind::DB::Writer::Serializer module when given asked to serialize a
series of maps which share some keys and values. It is used to test that
decoder code can handle pointers to map keys and values, as well as to the
whole map.
