Checks whether a string contains a template expression
function (content) {
    // Test against regex list
    var interpolateTest = _.templateSettings.interpolate.test(content);
    
    if (interpolateTest) {
        _.templateSettings.interpolate.lastIndex = 0;
        return true;
    }
    
    var evaluateTest = _.templateSettings.evaluate.test(content);
    
    if (evaluateTest) {
        _.templateSettings.evaluate.lastIndex = 0;
        return true;
    }
    
    var escapeTest = _.templateSettings.escape.test(content);
    _.templateSettings.escape.lastIndex = 0;
    return escapeTest;
}