Rule of 5 for Vec2F

Fix the following warning:

.././include/vector.h:125:5: warning: definition of implicit copy assignment operator for 'Vec2F' is deprecated because it has a user-declared copy constructor [-Wdeprecated-copy]

added low refactoring labels

assigned to @t.schroedter

mentioned in merge request !165 (merged)

mentioned in merge request !166 (merged)

closed with merge request !166 (merged)

mentioned in commit 5ce43476