Christmas Bird Count history report system

Each instance corresponds to one secondary entry on the regional index page. Secondary entries display as-published circle names for efforts whose names are not the same as the current circle name for the same latitude.

# - - - - -   c l a s s   S e c I n d e x

class SecIndex(BaseIndex):
    '''Represents an entry for a variant name.

      Exports:
        SecIndex(db, priIndex, variant, firstYear=MIN_YEAR,
                 lastYear=MAX_YEAR):
          [ (db is a pycbc.CBCData instance) and
            (priIndex is the related PriIndex instance) and
            (variant is a cir_name) ->
              return a new SecEntry representing all the efforts
              from priIndex.effortList whose names match variant ]
        .priIndex:     [ as passed to constructor, read-only ]
        .circle:       [ self.priIndex.circle ]
        .variant:      [ as passed to constructor, read-only ]
        .firstYear:    [ as passed to constructor, read-only ]
        .lastYear:     [ as passed to constructor, read-only ]
    '''