Image iterator

Containers:
* iterator, const_iterator, ... : à-la STL built-in iterators (dereferencing is not necessarily a Value)

 * ConstRange  : adapted from iterator (STLVector) or from the container (STLMap)
 * ConstRange::ConstIterator, ::ConstReverseIterator -> "*" returns a value

for CSetValueImage * image.setValue(point,val)

for CImage * OutputIterator (can be adapted from setValueImage)