Make player::is_habitable_feat() deal with deep water and lava.

git-svn-id: https://crawl-ref.svn.sourceforge.net/svnroot/crawl-ref/trunk@7876 c06c8d41-db1a-0410-9941-cceddc491573

Created by  zelgadis  on December 19, 2008
5MARZROV76J6EAZ724JAWUQICT5SCEPGPWUKR22DKGD22XD6QAFQC
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