Default class members require imports for their implementation

When a class member is a macro, a module importing that member needs to import the definitions from its implementation, which is logical. The same restriction now appears on default class members, however, and I don't think that is necessary. Consider the example below. Since Start uses the instance of [] there is no need for reverse to be present in test, but this is still required by the import system:

Error [test.icl,2,import]: function/macro reverse not imported

I think that the imports are only needed if the importing module contains an instance of the class that uses the default class member.

---

test.icl:

module test
from cls import class children(..), instance children []
Start = children_from_left [1,2,3]

cls.dcl:

definition module cls

from StdList import reverse

class children m
where
	children_from_left :: (m a) -> [a]
	children_from_left x = reverse (children_from_right x)
	children_from_right :: (m a) -> [a]
	children_from_right x = reverse (children_from_left x)

instance children []

cls.icl:

implementation module cls
instance children [] where children_from_left xs = xs