Skip reassignment of base value in Object::calculate_value

[heinezen]

For values that are assigned in parent members, the current value is calculated dynamically by traversing the linear history of the member and applying each change to the returned value. An example where this happens can be seen here:

First():
    member : int = 0

Second(First):
    member += 5

Third(Second):
    member += 3

When retrieving Third.member, Object::calculate_value searches for the base member that uses the assignment operator (in this case First.member) and then applies all operations in linear order (= 0, + 5, + 3) to arrive at the final value 8.

Since Object::calculate_value copies the initial return value from the base member, reapplying the assignment operation is superflous as it doesn't change the value. The reassignment can also create problems as seen in #118 because None doesn't allow reassignments. Therefore, the initial reassignment is now removed.

[TheJJ]

apart from the funny reformatting looking good!