remove unused build script

build/lib/download.js

-/*---------------------------------------------------------------------------------------------
- *  Copyright (c) Microsoft Corporation. All rights reserved.
- *  Licensed under the MIT License. See License.txt in the project root for license information.
- *--------------------------------------------------------------------------------------------*/
-
-'use strict';
-var https = require('https');
-var fs = require('fs');
-var url = require('url');
-
-function getOptions(urlString) {
-	var _url = url.parse(urlString);
-	return {
-		protocol: _url.protocol,
-		host: _url.host,
-		port: _url.port,
-		path: _url.path,
-		headers: {
-			'User-Agent': 'NodeJS'
-		}
-	}
-}
-
-exports.toFile = function (url, dest) {
-  return new Promise((c, e) => {
-		var file = fs.createWriteStream(dest);
-		var request = https.get(getOptions(url), function (response) {
-			response.pipe(file);
-			file.on('finish', function () {
-				var cb = (err, result) => err ? e(err) : c(result);
-				file.close(cb);
-			});
-		}).on('error', function (err) { // Handle errors
-			fs.unlink(dest); // Delete the file async, don't check the result
-			e(err.message);
-		});
-  });
-};
-
-exports.toString = function(url) {
-  return new Promise((c, e) => {
-	  var content = '';
-		var request = https.get(getOptions(url), function (response) {
-			response.on('data', function (data) {
-				content += data.toString();
-			}).on('end', function () {
-				c(content);
-			});
-		}).on('error', function (err) {
-			e(err.message);
-		});
-  });
-}
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