tidy_data: tidy_data
In caimiao0714/MiaoTruck: Data manupulation for the NSF truck data.

This function cleans the driver data and returns the cleaned dataset.

1 2	tidy_data(data, threshold_hour = 8, thre_tem = 0, thre_visul = 1000, delete_duplicate = TRUE)

`data`	the data to be cleaned.
`threshold_hour`	The threshold of hour to segment the speed data
`thre_tem`	The upper threshold of temperature to decide extreme temperature conditions. The unit of thre_tem is 1 cesius degree. The default value is 0 cesius degree.
`thre_visul`	The upper threshold of visibility distance to decide extreme temperature conditions. The unit of thre_visul is 1 meter. The default value is 1000 meters.
`delete_duplicate`	where the duplicated data points are to be deleted. The default value is TRUE, which means the duplicated data points will be deleted by default.