First proof of concept, fixing the original bug for Russian.
Added gramps/gen/datehandler/_datestrings.py, to hold
all the localized strings, with genitive/nominative
context as appropriate.
Remaining TODO:
1) other languages
2) expand the localized string into RE-style
concat via |, so that displayer uses the 1st instance,
and the parser uses the whole RE. Write the corresponding _().
3) same with short names as with long names
4) harmonize with _grampslocale code reading the names from
elsewhere for Julian/Gregorian months
5) expand to other calendars (non-Julian/non-Gregorian)
6) obsolete the public attributes in dd and replace with accessors
svn: r23173
6eebd80dfc