Update street count when deleting streets from gallery. Close #354.
Update street count when deleting streets from gallery. Close #354.

macGRID-SRN/streetmix,CodeForBrazil/streetmix,magul/streetmix,magul/streetmix,kodujdlapolski/streetmix,codeforamerica/streetmix,codeforamerica/streetmix,macGRID-SRN/streetmix,kodujdlapolski/streetmix,CodeForBrazil/streetmix,magul/streetmix,kodujdlapolski/streetmix,macGRID-SRN/streetmix,CodeForBrazil/streetmix,codeforamerica/streetmix