add transactions around most page generations to speed up temporary table/view creation; fix bug: make _add_periods_to_controversy_dump deal correctly with dumps with no custom dates
add transactions around most page generations to speed up temporary table/view creation; fix bug: make _add_periods_to_controversy_dump deal correctly with dumps with no custom dates

berkmancenter/mediacloud,AchyuthIIIT/mediacloud,AchyuthIIIT/mediacloud,AchyuthIIIT/mediacloud,AchyuthIIIT/mediacloud,berkmancenter/mediacloud,AchyuthIIIT/mediacloud,AchyuthIIIT/mediacloud,berkmancenter/mediacloud,AchyuthIIIT/mediacloud,berkmancenter/mediacloud,berkmancenter/mediacloud,AchyuthIIIT/mediacloud,AchyuthIIIT/mediacloud