Building project with ARUCO fails

I'm trying to build a project with arUco.

I am using openCV v.3.1, which apparently includes aruco. However, I get the error:

opencv2/aruco/dictionary.hpp: No such file or directory
    #include "opencv2/aruco/dictionary.hpp"
                                           ^

I then downloaded arUco, built it, and tried to build the example described at the bottom of http://www.uco.es/investiga/grupos/ava/node/26 . I get the error:

fatal error: aruco/aruco.h: No such file or directory
    #include <aruco/aruco.h>
                            ^

The CMakeLists.txt used is:

cmake_minimum_required(VERSION 2.8)
project(aruco_testproject)
SET(CMAKE_MODULE_PATH ${CMAKE_INSTALL_PREFIX}/lib/cmake/ )
MESSAGE(${CMAKE_MODULE_PATH})
find_package(aruco REQUIRED )
add_executable(aruco_simple aruco_simple.cpp)
target_link_libraries(aruco_simple  ${aruco_LIBS})

I've copied Findaruco.cmake to /usr/local/lib/cmake/

If anyone could help, that'd be fantastic. I've been looking for a solution for a while and I feel really stuck. Thanks a lot!