Remove all the children in the given collection from this node’s list of children.
This method allows you to pass in any ICollection, rather than a PNodeList. This can be useful if you are using an ArrayList or some other collection type to store PNodes. Note, however, that this list still must contain only objects that extend PNode otherwise you will get a runtime error. To protect against problems of this type, use the RemoveChildren(PNodeList) method instead.
All removed nodes will have their parent set to null.