Should we special-case the cwipc_read() error if the file looks like a git pointer?

[jackjansen]

@troeggla assigning to you mainly for feedback.

Just get the third report of someone trying to read point clouds from one of our repos (cwipc_test in this case) and getting strange errors because they hadn't enabled git lfs (cwi-dis/cwipc_unity_sample#1).

Is it worth it to give a special error message for this? It's fairly easy to implement (if we see that we get an error message from the underlying ply reader, or if the cwipcdump reader gets an incorrect header do a quick check whether the file looks like a git pointer), and an error like cwipc_read: point cloud file read error, looks like a git lfs pointer would be helpful for the user.

Or am I over-engineering?