Up/down SBGN Tags are not fully supported by the converter

[ibalaur]

Curently, only the SBGN Tags with left/right orientation have direct representations in the yEd SBGN Palette, while the SBGN up/down Tag elements do not have.
Due to this limitation, an SBGN up/down Tag element is translated by the converter into a Tag element with orientation to left.
See the "tags" forlder: https://github.com/sbgn/ySBGN/tree/master/example_files/tags