Random and trending work, normal data does not

Added selection for data type.
Rewrote random data generation into it's own function.
Created trending_data function. Add random interger between -2 and 5 to
the previous value in the data_values list. -2 was used so non perfectly
trending data would be created.
Trending data still needs work; randint range is arbitrary and should be
tied to users min and max values.