Users are now notified of errors associated with incorrect pv entry and deletion attempts using sternly worded message boxes.
Fixed bug where pvs added after the time window is changed do not reflect this change! Now, every pv added before or after the time window is changed adhere to the new window. Also added a 'granularity' field in the EditPVDialog, where the user can set whether they want the plot to update with every pv update, or every other update, etc...