Implement more endpoints & overhaul [2/n]

Drop LevelDB and move all the things to SQLite.

Implemented endpoints:
/api <unit, accessoryMaterialAll>
/api <unit, accessoryTab>
/live/continue
/live/partyList
/unit/favoriteAccessory (WIP)
/unit/sale

Signed-off-by: Sean Du <do4suki@gmail.com>

main.go

@@ -27,8 +27,9 @@ func main() {
 
 	go func() {
 		<-signalChan
-		log.Println("Shutting down...")
-		db.Ldb.Close()
+		log.Println("正在退出...")
+		db.MainEng.Close()
+		db.UserEng.Close()
 		os.Exit(0)
 	}()