Fix for Mantis 2982: Removes superfluous Assert.


git-svn-id: svn://svn.icculus.org/fs2open@10820 387891d4-d844-0410-90c0-e4c51a9137d3
From MageKing17: Patch for Mantis 3012 (Various issues with ships in nebula)

git-svn-id: svn://svn.icculus.org/fs2open@10821 387891d4-d844-0410-90c0-e4c51a9137d3
From MageKing17: Patch for Mantis 3061 (Turrets can't have an initial rotation defined)

git-svn-id: svn://svn.icculus.org/fs2open@10822 387891d4-d844-0410-90c0-e4c51a9137d3
From MageKing17: Patch for Mantis 3060 (Beam particles not generated correctly in certain cases)

git-svn-id: svn://svn.icculus.org/fs2open@10823 387891d4-d844-0410-90c0-e4c51a9137d3
Fix for Mantis 3016 (Briefing window FOV different from retail).
Also adds a new setting to game_settings.tbl, "$Briefing Window FOV:" under Graphics, which takes a single float argument to set the FOV of the briefing window.


git-svn-id: svn://svn.icculus.org/fs2open@10824 387891d4-d844-0410-90c0-e4c51a9137d3