Addition of sinking to battle log

[seawolf]

In the current battle log for individual ships, it tells when they start sinking, but not when they go down.

It would be nice to have something like:

15 14:35 Ship sinking.
15 14:57 Ship goes under.

[seawolf]

SAI actually has
-Ship Sunk
in the message logs,
I don't know why it was disabled