v0.3.4

parse yyy-yy date string

• fix latest_year to correctly parse values such as "950-60" (i.e. 960)

parse yyy-yyyy date string

• fix earliest_year to correctly parse values such as "996–1021 CE" (i.e. 966)

parse year to year date string

• fix latest year to correctly parse values such as "1500? to 1582" (i.e. 1582)