revert and keep win32 asyncio

cq_editor/__main__.py

@@ -1,19 +1,12 @@
 import sys
-import os
 import asyncio
 import argparse
-import faulthandler
-
-from PyQt5.QtWidgets import QApplication
-
-faulthandler.enable()
-
-if 'CASROOT' in os.environ:
-    del os.environ['CASROOT']
 
 if sys.platform == 'win32':
     asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())
 
+from PyQt5.QtWidgets import QApplication
+
 NAME = 'CQ-editor'
 
 #need to initialize QApp here, otherewise svg icons do not work on windows