Christmas Bird Count history report system

This is a pass-through from the ColumnLayout instance to avoid a violation of the http://en.wikipedia.org/wiki/Law_of_Demeter.

# - - -   C b c H i s t . c o l L a b e l

    def colLabel(self, k):
        '''Returns the label for column [k].
        '''
        return self._columnLayout.label(k)