-Replace the seg gap repair code with Killough's code to avoid the sine/cosine tables and a call to sqrt.
-Moving seg vertices can break demo compatibility so only call P_RemoveSlimeTrails when not playing or recording a demo.

git-svn-id: http://odamex.net/svn/root/trunk@3911 b0bcef46-2027-0410-bd56-ab726e9a1d04
-Fix a small compilation issue in r3899.

git-svn-id: http://odamex.net/svn/root/trunk@3912 b0bcef46-2027-0410-bd56-ab726e9a1d04