Visuals

I have adapted the patch from issue 724 by alexghir9 following the
suggestion from Edvin
Visuals updated

Made some changes following suggestions from AlbertFree
Thanks
Comment updated

As per suggestion from Albet
Visuals

allows #visuals_available  gbv.HoldVisual gbv.HoldVisualPeepCount to be
used by the game to determine if and when a visual disease can appear
in-game
Merge pull request #34 from MarkL1961/visuals

Use config setting to determine when Visual disease can appear