Changes

Units are objects in Prism3d that have ability to be serialized or deserialized.

* Name - units can be nameless or have some specified name names are divided into components which are 12-char tokens separated by dot - for example correct unit name will be <code>vehicle.dummy.truck</code> however in most cases you should not use them as in case engine detects two units with the same name it will fail so in case some mod is using name <code>vehicle.dummy.truck</code> and you will also use this your mod will fail to load. To create nameless unit simply use dot as the prefix for your unit name for example <code>.my_mod.nameless.units</code>