Version 2.8

Pulled in matplotlib #7894 "Bug Fix: DraggableBase not to move unselected object" by fukatani. This fixes a really annoying bug which made dragging User Notes and User Event strings to new positions quite difficult. Frequently objects which you formerly selected would get dragged along with the current object you were trying to move. With fukatani's fix, dragging is greatly improved.

This release also includes changes to better handle large data sets. After running for a year, there are over 100000 blood glucose data points. Reading them all in every 5 minutes was slowing down performance. Under a new scheme, we read in 105 days at a time. If the user scrolls to a time outside that range, we adjust the start and end points of the selection range, but still read just 105 days of data. This keeps performance consistent, no matter how many data points are in the database.