Load a formatter
@param  {String} formatterPath
@return
function loadFormatter(formatterPath) {
    try {
        // @TODO: deprecate
        formatterPath = (formatterPath === 'jslint_xml') ? 'jslint' : formatterPath;
        return require('./lib/' + formatterPath + '_emitter');
    } catch (e) {
        console.error('Unrecognized format: %s', formatterPath);
        console.error('This emitter was not found on lib folder.\nYou can always create yours :)\n');
        throw e;
    }
}