Remove event.time since it is hardly (ever?) used.

People who want it can do it themselves easy enough.

Author: GraylinKim

sc2reader/events.py

@@ -12,7 +12,8 @@ def __init__(self, frame, pid):
         self.pid = pid
         self.frame = frame
         self.second = frame >> 4
-        self.time = Length(seconds=self.second)
+        # This is sorta expensive considering no one uses it
+        # self.time = Length(seconds=self.second)
 
     def load_context(self, replay):
         if self.pid != 16: