Updated core device subclasses (Pseudoclock, ClockLine, TriggerableDevice, IntermediateDevice, etc.) to more modern Python and improved some formatting.

Also fixed a bug in an error message.

Author: philipstarkey

labscript/base_device.py renamed to labscript/base.py

@@ -406,7 +406,7 @@ def parent_clock_line(self):
     @property
     def t0(self):
         """float: The earliest time output can be commanded from this device at
-            the start of the experiment. This is nonzeo on secondary pseudoclock 
+            the start of the experiment. This is nonzero on secondary pseudoclock 
             devices due to triggering delays."""
         parent = self.pseudoclock_device
         if parent is None or parent.is_master_pseudoclock: