BGを実装.

SMILEBASIC/SMILEBASIC.visualdproj

@@ -205,6 +205,7 @@
   <filesToClean>*.obj;*.cmd;*.build;*.json;*.dep</filesToClean>
  </Config>
  <Folder name="SMILEBASIC">
+  <File path="bg.d" />
   <File path="builtinfunctions.d" />
   <File path="compiler.d" />
   <File path="draw.d" />