Added day_start and day_end properties.  Useful for a group_by day of events.
Added day_start and day_end properties.  Useful for a group_by day of events.

erlanger-ru/erlanger-ru.meta,erlanger-ru/erlanger-ru.meta,erlanger-ru/erlanger-ru.meta,erlanger-ru/erlanger-ru.meta,erlanger-ru/erlanger-ru.meta