CanJS : can-define behaviours (weekly-training-topics)

When defining a DefineMap/List what do we need to use and how do we use it?
The difference between Type/type/Value/value is very confusing.

This is how we define a DefineMap typically (setting a default value for every property).

```
import DefineMap from 'can-define/map/map';

export default DefineMap.extend({
children : {
value : []
},
hasChildren : {
value : false
},
classes : {
value : ''
},
path : {
value : null
}
});

```

Start with the DefineMap example in the issue and compare the DefineMap/List behaviours it asks about. Document when to use Type, type, Value, and value, including how default values are defined; done when the guidance clearly explains each choice and its usage.

Written by the indexing model from the issue text.