Fix pyinstaller standalone generation

labelme.spec

@@ -6,7 +6,7 @@ block_cipher = None
 
 
 a = Analysis(
-    ['labelme/app.py'],
+    ['labelme/main.py'],
     pathex=['labelme'],
     binaries=[],
     datas=[

labelme/main.py

@@ -117,3 +117,7 @@ def main():
     win.show()
     win.raise_()
     sys.exit(app.exec_())
+
+
+if __name__ == '__main__':
+    main()