Merge pull request #89 from pathmapper/fix_town_hall

Fix townhall icon name to match vt source

sprites/osm-liberty.json

@@ -1546,14 +1546,14 @@
     "x": 105,
     "y": 208
   },
-  "town-hall_11": {
+  "town_hall_11": {
     "height": 17,
     "pixelRatio": 1,
     "width": 17,
     "x": 370,
     "y": 94
   },
-  "town-hall_15": {
+  "town_hall_15": {
     "height": 21,
     "pixelRatio": 1,
     "width": 21,

sprites/osm-liberty@2x.json

@@ -1546,14 +1546,14 @@
     "x": 210,
     "y": 416
   },
-  "town-hall_11": {
+  "town_hall_11": {
     "height": 34,
     "pixelRatio": 2,
     "width": 34,
     "x": 742,
     "y": 188
   },
-  "town-hall_15": {
+  "town_hall_15": {
     "height": 42,
     "pixelRatio": 2,
     "width": 42,