Function cases

cases<T>(defaultExpression): CaseExpression<T>
Returns an expression that can be used to chain multiple when-then statements together. On the returned case expression, you can add cases by calling when with an expression and subsequently call then with another expression. This creates a chain of if-then-else statements. If no cases match, the result of the default expression is used. The expression given as argument to a when-call should result in boolean.
```
var defaultExpression = ...;
var someTestExpression = ...;
var someResultExpression = ...;
var someOtherTestExpression = ...;
var someOtherResultExpression = ...;

var caseExpression = ExpressionFactory.cases(defaultExpression);
caseExpression.when(someTestExpression).then(someResultExpression)
              .when(someOtherTestExpression).then(someOtherResultExpression);
```
Type Parameters
- T extends string | number | Vector3
Parameters
- defaultExpression: Expression<T>
  The expression evaluated if no when-then case is met.
Returns CaseExpression<T>
A case expression that can be used to add when-then cases.