check for OpenCV 3.(2+)

[JStech]

When building with OpenCV 3.4, the target markers fail with this error:

moveit_calibration/moveit_calibration_plugins/handeye_calibration_target/src/handeye_target_charuco.cpp:196:17: 
    error: ‘struct cv::aruco::DetectorParameters’ has no member named ‘cornerRefinementMethod’; did you mean 
    ‘cornerRefinementWinSize’?
 params_ptr->cornerRefinementMethod = cv::aruco::CORNER_REFINE_NONE;

This is because the correct code for OpenCV 3.4 is guarded by preprocessor checks that specifically look for 3.2. This PR just switches that check to pass for any minor version >=2. (Related to #5 .)

[AndyZe]

I tested this with OpenCV 3.2 and it fixed a build error. 👍

Did not test functionality.

[AndyZe]

Actually there was an issue (I forgot to remove a CATKIN_IGNORE file from the package). I seem to still have a build error.

[JStech]

Well, now I'm all confused. It does look like 3.2.0 uses the doCornerRefinement parameter, but 3.4.5 uses cornerRefinementMethod, but this change does seem to fix a build on 3.4 for us. I'm going to close this PR for now.