EventReport.stat file not found error handling (#281)

* Updated the e-ph plotting script

* Make use of decorators for band structures

* Modified EventReport.stat to allow for paths that are not found on the local machine.

* Clean up of old stuff.

abipy/flowtk/events.py

@@ -273,7 +273,10 @@ def __init__(self, filename: str, events=None):
             events: List of Event objects
         """
         self.filename = os.path.abspath(filename)
-        self.stat = os.stat(self.filename)
+        try:
+            self.stat = os.stat(self.filename)
+        except FileNotFoundError:
+            self.stat = None
         self.start_datetime, self.end_datetime = None, None
 
         self._events = []