Let children() return an (pseudo-)immutable array-like 

Has "first()" and "last()", but also implements the most important array
methods (that don't modify the array), and an toArray method. Unlike
e.g. jQuery the methods are called and behave exactly like the array
methods.

Change-Id: I4b55bdb89ca4c8a3f87d9a9c74d184586860c75e