Read all existing glossaries in the main aux-file.

def read_glossaries(self):
        '''
        Read all existing glossaries in the main aux-file.
        '''
        filename = '%s.aux' % self.project_name
        with open(filename) as fobj:
            main_aux = fobj.read()

        pattern = r'\\@newglossary\{(.*)\}\{.*\}\{(.*)\}\{(.*)\}'
        for match in re.finditer(pattern, main_aux):
            name, ext_i, ext_o = match.groups()
            self.glossaries[name] = (ext_i, ext_o)