ve.dm.ContentBranchNode#lastApproved should be directional #27
Description
Because if X machine translates to Y, it doesn't necessarily imply Y machine translates back to X.
Example: s'il te plaît --mt--> please --mt--> s'il vous plaît .
This results in horrible diff conflicts if you write X1, accept the machine translation Y1, and then modify it to Y2. We then believe Y1 machine translates to X1 but actually it may translate to something quite different.
We can fix it by storing translation direction: X->Y, Y->X'