Update to build on Xcode 6.0: Revert to non-hacked version of llphysicsextensions package now we can link

Update to build on Xcode 6.0: remove #pragmas from code to deal with tut warnigs/errors (moved to package) AND bracket clang #pragmas in #if LL_DARWIN

Update to build on Xcode 6.0: Remove concept of XCODE_VERSION from CMake files - we standardize on Xcode 6

Update to build on Xcode 6.0: Large (and final) collection of fixes for unused variables, unused const-variables, unused member variables & functions etc. Also removed flags from CMake

Update to build on Xcode 6.0: clarify list of things left to do now llphysics_extension hack is in place

Update to build on Xcode 6.0: point to temporary, hacked version of llphysics_extensions that remove the unusd variables (and therefore warnings/errors) - see TODO list

Update to build on Xcode 6.0: fix member initializer 'mWaitingToClose' does not name a non-static data member or base class