CMake compatibility

Line 25 in ab817b7

    
           PATCH_COMMAND patch -p1 -t -N < ${CMAKE_SOURCE_DIR}/patch/eigen-3.2.8-no-malloc-in-llt.patch

Is it possible to change ${CMAKE_SOURCE_DIR} to ${PROJECT_SOURCE_DIR}? This will allow others to add this repo as a subdirectory to their CMake governed project, without breaking the local reference to the eigen3 patch.

Thanks,
Reinier

Fixed in #45, thanks @aronhoff

For those who got here from google, you don't need add_subdirectory(ukf). Just add ukf/include to your include_directories call and you're good to go. No linking necessary.