Remove xcodeproj in favor of cmake

I'll rise my point once again - manually maintaining 3 kinds of projects for 3 main platforms is a way to nowhere. If you want real world examples - Epic's UE4 has it own UnrealBuild, Valve's Source has Valve Project Creator, Chromium/V8 has GYP.

Thanks god I'm not proposing to start yet another meta build system development. CMake is the most popular open source tool that matches this philosophy. It's used by many big projects KDE, OpenCV, Clang/LLVM, OGRE etc.

Currently despite it's idea CMake makes things even worse for QFusion because there is 4 project files to maintain. So I propose to start process of full migration to CMake starting from OS X. Right now we have a time window after 1.5 release so  there would be time to test things.