Time values in summary tables

[HenningoDK]

I have a few issues with the summarized time values in 'garmin_summary.db'.

[weeks_summary].[intensity_time]: This appears to be calculated as an average of the non-zero values from [days_summary].[intensity_time].
Same issue applies to [weeks_summary].[moderate_activity_time].
I think the correct calculation for these would be the sum of the values found in the [days_summary] table. The field [weeks_summary].[vigorous_activity_time] is already calculated correctly as the sum.

In tables [months_summary] and [years_summary] there is an issue when the summarized values (intensity_time, moderate_activity_time, vigorous_activity_time) exceed 24 hours.