Unnecessary ERROR when open up TIM for the first time.

[Angus Yeh]

-ERROR Failed to read plot list C:/Users/cyeh015.en-354404/AppData/Roaming/TIM/plot_with_elevation.json as JSON format. -ERROR Exception: [Errno 2] No such file or directory: 'C:/Users/cyeh015.en-354404/AppData/Roaming/TIM/plot_with_elevation.json' -ERROR Failed to read plot list C:/Users/cyeh015.en-354404/AppData/Roaming/TIM/time_history_plot.json as JSON format. -ERROR Exception: [Errno 2] No such file or directory: 'C:/Users/cyeh015.en-354404/AppData/Roaming/TIM/time_history_plot.json'

[Angus Yeh]

Should be okay after commit 6a73c43 now.