#128 Figure 2.1 in PD spec is incorrect SBGN

[Anonymous]

According to the SBGN specification, edges are not allowed to overlap, however the edges for catalysis overlap in the figure.

Since even the SBGN editors seem to do something like this, it stands to reason that is is something people actually want to do, so disallowing it might not
be a good idea.

[Nicolas Le Novère]

I corrected the two figures containing this mistake