Changing screaming mutation to influence both frequency

and volume of shouting -> yelling -> screaming. Reduced frequency of level 2 and 3 to make up for greater range. When paralysed, you are unable to scream.

Also cleaning up mutation listings.

git-svn-id: https://crawl-ref.svn.sourceforge.net/svnroot/crawl-ref/trunk@2517 c06c8d41-db1a-0410-9941-cceddc491573

Created by  j-p-e-g  on October 22, 2007
Z63Q4DA5J5TZAC5LN55UD4CLADUMU5Z73TGEVE2YUXCHIST2Y4QAC
Change contents