Handle missing temp files during cleanup (#188)

Author: l1va

src/process.py

@@ -53,7 +53,10 @@ def __del__(self):
             self.kill()
         for f in self._files.values():
             f.close()
-            os.unlink(f.name)
+            try:
+                os.unlink(f.name)
+            except FileNotFoundError:
+                pass
 
     @property
     def pid(self):