Update simplify_map.R
Update simplify_map.R

V() was throwing an Vertex Index Error. I believe this may be due to using a later version of igraph (v0.7). This fix removes the error and does not cause backwards compatibility problems.
NYPL/map-vectorizer,tlevine/map-vectorizer,tlevine/map-vectorizer,nypl-spacetime/map-vectorizer,nypl-spacetime/map-vectorizer,NYPL/map-vectorizer