do 304 requests and cache them in sqlite

src/map/vector_tile_data.cpp

@@ -30,18 +30,18 @@ void VectorTileData::parse() {
         return;
     }
 
-    try {
+//    try {
         // Parsing creates state that is encapsulated in TileParser. While parsing,
         // the TileParser object writes results into this objects. All other state
         // is going to be discarded afterwards.
         parser->parse();
-    } catch (const std::exception& ex) {
-#if defined(DEBUG)
-        fprintf(stderr, "[%p] exception [%d/%d/%d]... failed: %s\n", this, id.z, id.x, id.y, ex.what());
-#endif
-        cancel();
-        return;
-    }
+//    } catch (const std::exception& ex) {
+//#if defined(DEBUG)
+//        fprintf(stderr, "[%p] exception [%d/%d/%d]... failed: %s\n", this, id.z, id.x, id.y, ex.what());
+//#endif
+//        cancel();
+//        return;
+//    }
 
     if (state != State::obsolete) {
         state = State::parsed;