fix the compilation bug of main.cpp in perf test and accuracy test on ocl module. It caused by the incompatibility of command line parser class in core.hpp between master branch and 2.4 branch.

another fix to make OpenCV more friendly for iOS developers. We now use libc++ instead of libstdc++ and clang instead of gcc to build opencv2.framework.

Memory leak in color-blob-detection sample fixed;
Default face size in face-detection is set to 20%;
Error handling improved;
Some possible mat leak fixed;
Manager verison and engine interface version incremented to fix incompatibilities;
Docs updated;