Fix CMakeLists.txt

[Shimmen]

I found some issues with the CMakeLists.txt build script which I fixed:

1. According to Google there is no CMake function/macro called setup_target_libs, and CMake (recent version) fails when executing the CMakeLists.txt script. It might be an artefact from the project this was originally created for(?). Either way, this pull request simply removes that line.
2. The project did not have any include directories specified, so if you added the project with target_link_libraries(MyTarget offsetAllocator) the header would not be identified. Adding the call to target_include_directories fixes this.

Thanks!

// Simon