Overwriting define validate options breaks other instances of same map

[Macrofig]

The map plugin will overwrite the validate object with the processed property. This is because, in some cases, we allow some validation options to pass a function that check other properties in the map instance. This causes problems whenever multiple instances are created of the same map; every instance created after the first will point to the first instance and use that instance for any checks.

Need to refactor how the created computes are stored and retrieved.

[Macrofig]

Fixed in PR #29