Further cleanup Xcode 4/5 project file. Promote settings to top level where possible, remove redundant GCC settings

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@10037 387891d4-d844-0410-90c0-e4c51a9137d3
Further Xcode 4/5 project file cleanup. Install setting not required as we build an .app bundle

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@10038 387891d4-d844-0410-90c0-e4c51a9137d3
Xcode 4/5 project file cleanup. Further deprecated settings related to cfilearchiver

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@10039 387891d4-d844-0410-90c0-e4c51a9137d3
Xcode 4/5 project file cleanup. These are redundant settings

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@10040 387891d4-d844-0410-90c0-e4c51a9137d3
Re-enable -Wno-shorten-64-to-32 for Xcode. There remains code in the project, including third party, that assumes implicit 64->32 casts are permitted, which the expectation of overflow. We'll need to re-enable this warning later and revisit specific cases in question, either adding an explicit cast, or handling any cases where overflow is theoretically possible and undersired.

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@10041 387891d4-d844-0410-90c0-e4c51a9137d3
LLVM warning: Initialization of pointer of type 'bool *' to null from a constant boolean expression

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@10042 387891d4-d844-0410-90c0-e4c51a9137d3