Implement w1 + w2 for objects
>> w = w1 + w2
if w1, w2 are objects of the same size:
- the operation is performed element-by-element
if one of w1 or w2 is numeric:
- if a scalar, apply to each element of the object numeric array
- if an array of the same size as the object numeric array, apply
element by element
w1, w2 can be arrays:
- if objects have same array sizes, then add element-by-element
- if an (n+m)-dimensional array, the inner n dimensions will be
combined element by element with the object numeric array (where
n is the dimensionality of the object numeric array), and the
outer m dimensions must match the array size of the array of objects