Nice to hear that you find it useful!

Now it is also documented online: gsvec docs

There were a few minor bugs in the code or rather mistakes in the documentation:

* ll_vec_distSegLine(): the line is NOT defined by the first but by the second line segment
* ll_vec_distPointSeg(): does not return only 0 or 1, but also 2 and 3 (depending on the case)
* ll_vec_intersectSegPlane(): same as above

I've uploaded the corrected version of the code (same link as before).