Fix cppcheck (warning) Logical conjunction always evaluates to false: logfile_type < 0 && logfile_type >= 2.

git-svn-id: svn://svn.icculus.org/fs2open@11012 387891d4-d844-0410-90c0-e4c51a9137d3
Fix cppcheck (style) Same expression on both sides of ||.

git-svn-id: svn://svn.icculus.org/fs2open@11013 387891d4-d844-0410-90c0-e4c51a9137d3
Fix cppcheck (style) Consecutive return, break, continue, goto or throw statements are unnecessary.

git-svn-id: svn://svn.icculus.org/fs2open@11014 387891d4-d844-0410-90c0-e4c51a9137d3
Fix cppcheck (performance) Prefer prefix ++/-- operators for non-primitive types.

git-svn-id: svn://svn.icculus.org/fs2open@11015 387891d4-d844-0410-90c0-e4c51a9137d3