Experimental support for monster shields, needs more work for rationalising shield class for monsters with player and beam to-hit.

git-svn-id: https://crawl-ref.svn.sourceforge.net/svnroot/crawl-ref/trunk@2727 c06c8d41-db1a-0410-9941-cceddc491573

Created by  dshaligram  on November 2, 2007
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