MOHAWK: RIVEN: Let credits roll longer

Fixes Trac#10675.

Previously, the credits ended as soon as the last row was shown
of the final credits image.

Now some more black rows (empty rows) are shown and finally a few
seconds of black. I set it to 8 seconds of wait beyond where
the credits where previously stopping.

In order to do this updateCredits was enhanced to work past the end
of the last credits image (and just keep adding empty rows).

The original game shows a black screen for a longer period than this.

The credit image numbers are turned into enums.

0 files changed, 0 insertions, 0 deletions