Use vtzero in tile plugin.
Use vtzero in tile plugin.

This uses the new vtzero library (https://github.com/mapbox/vtzero)
instead of using protozero directly.

Project-OSRM/osrm-backend,yuryleb/osrm-backend,oxidase/osrm-backend,frodrigo/osrm-backend,bjtaylor1/osrm-backend,yuryleb/osrm-backend,bjtaylor1/osrm-backend,yuryleb/osrm-backend,oxidase/osrm-backend,oxidase/osrm-backend,bjtaylor1/osrm-backend,Project-OSRM/osrm-backend,frodrigo/osrm-backend,Project-OSRM/osrm-backend,felixguendling/osrm-backend,bjtaylor1/osrm-backend,felixguendling/osrm-backend,frodrigo/osrm-backend,yuryleb/osrm-backend,Project-OSRM/osrm-backend,felixguendling/osrm-backend,oxidase/osrm-backend,frodrigo/osrm-backend