Returns the absolute path to the qooxdoo framework used by the current project
@return {Promise(String)} Promise that resolves with the path {String}
async function() {
      let compileJsonPath = null;
      try {
        path.join(await this.getApplicationPath(), "compile.json");
      } catch (ex) {
        // Nothing - cannot find compile.json
      }
      if (compileJsonPath && await fs.existsAsync(compileJsonPath)) {
        let compileConfig = await this.parseCompileConfig();
        let qxpath = false;
        let appPath = await this.getApplicationPath();
        if (compileConfig.libraries) {
          for (let somepath of compileConfig.libraries) {
            let manifestPath = somepath;
            if (!path.isAbsolute(somepath)) {
              manifestPath = path.join(appPath, manifestPath);
            }
            manifestPath = path.join(manifestPath, "Manifest.json");
            let manifest = await this.parseJsonFile(manifestPath);
            try {
              if (manifest.provides.namespace === "qx") {
                qxpath = path.dirname(manifestPath);
                return qxpath;
              }
            } catch (e) {
              console.warn(`Invalid manifest file ${manifestPath}.`);
            }
          }
        }
      }
      return this.getGlobalQxPath();
    }