function describeConstant(key,value) {
        var desc = { name:key, value:value, type:'constant' };
        // perhaps add, value = function support
        return desc;
      }
@ngdoc method
@name ss.bundler:bundler#systemModule
@methodOf ss.bundler:bundler
@function
@description
Describe a system module.

@param {String} name Name of the system module to return in a descriptor
@param {boolean} wrap Shall the content be wrapped in `require.define`. Default is true.
@returns {AssetEntry} Entry