Make sh_text and sh_stext optional. Since sh_text depends on pango, and we want a version of MadButterfly without Pango (lite version), we make sh_text and sh_stext optional. User can choice which one to enable.

function start_madbuilder() {
    var url = "chrome://MadBuilder/content/madbuilder.html";
    var browser = document.getElementById("content");

    browser.loadURI(url, null, null, true);
}