We should use a version from OpenCV's 2.x branch. The C API was deprecated in OpenCV 3.x, and stuff breaks (see #335, #251). Plus, there really is no need to use OpenCV 3. We use non of its features. The 2.x branch is still maintained by OpenCV folks.
If there are mentions of OpenCV 3 in the documentation, they should be replaced. If some of the build scripts either use OpenCV 3 or do not specifically use 2.x, they should be fixed, too.
We should use a version from OpenCV's 2.x branch. The C API was deprecated in OpenCV 3.x, and stuff breaks (see #335, #251). Plus, there really is no need to use OpenCV 3. We use non of its features. The 2.x branch is still maintained by OpenCV folks.
If there are mentions of OpenCV 3 in the documentation, they should be replaced. If some of the build scripts either use OpenCV 3 or do not specifically use 2.x, they should be fixed, too.