Writes all jdoc records into files.
        One file per schema plus index file.

def write_files(self, jdoc, output_dir):
        '''Writes all jdoc records into files.
        One file per schema plus index file.'''

        #get all distinct schema names from jdoc:
        schemas = [j for j in jdoc if j.object_type == 'schema']
        schemas = [j for j in schemas if len([x for x in jdoc if x.object_type != 'schema' and x.schema_name == j.object_name]) > 0]
        if not os.path.exists(output_dir):
            os.makedirs(output_dir)
        try:
            shutil.copytree(self.template_dir + os.sep + 'styles',
                            output_dir + os.sep + 'styles')
        except FileExistsError:
            None
        for schema in schemas:
            with open(output_dir + os.sep + schema.object_name + '.html', 'w') as f:
                f.write(self.generate_html(jdoc, schema, schemas))
        with open(output_dir + os.sep + 'index.html', 'w') as f:
            f.write(self.generate_index(schemas))