release 0.15.12

[forrestguice]

• increases the range of supported dates from +-2.5 years to +-500 years (View Date limited to 1000 days in the past #770).
• fixes bug where date selector allows selecting unsupported dates (closes View Date limited to 1000 days in the past #770), and other miscellaneous UI changes.
• fixes bug where alarm screen back button overlaps the dismiss button (closes keep the back button away from dismiss button #777).
• fixes bug in date widget where the scaled text is not centered (closes Very big font size for date widget #763).
• fixes ambiguity in minutes abbreviation; replaces "m" with "min" for all translations that default to metric (Add day length difference from the day before and fix minute symbol #773).
• updates translation to Russian (ru) (added translations to Russian #775 by Adelechka). translation to ru (Russian) #683