code: function _gpfLoadSources () { //jshint ignore:line
      var sourceListContent = _gpfSyncReadForBoot(gpfSourcesPath + "sources.json"),
          _gpfSources = _GpfFunc("return " + sourceListContent)(),
          allContent = [],
          idx = 0;
      for (; idx < _gpfSources.length; ++idx) {
          _gpfProcessSource(_gpfSources[idx], allContent);
      }
      return allContent.join("\n");
  }
docs: Load content of all sources
  
  @return {String} Consolidated sources
  @since 0.1.9