v0.7.15

http://miew.opensource.epam.com/v0.7.15/

Fixed

• Fix a crash when a non-integer unit index is set.
• Fix message about current unit after try to change.
• Use default gradient color for the case of no temperature/occupancy.
• Use average temperature and occupancy for residue coloring.
• Use groupId as a sequence index for MMTF.