fix(webdriver-manager): fix IEDriver install and running via windows

Changed the binaries.ie.url function to return the correct URL for the IEDriverServer.
Created the zip object in the win32 section to be able to decompress IEDriverServer.
Added a function to normalize a command across OS and spawn it. It allows start the webdriver in win32.

Seen here:
https://github.com/yeoman/generator/blob/master/lib/actions/spawn_command.js

bin/webdriver-manager

@@ -56,11 +56,9 @@ var binaries = {
       var urlPrefix = 'https://selenium.googlecode.com/files/IEDriverServer';
       if (os.type() == 'Windows_NT') {
         if (os.arch() == 'x64') {
-          binaries.iedriver.url = urlPrefix + '_x64_' + versions.iedriver +
-              '.zip';
+          return urlPrefix + '_x64_' + versions.iedriver + '.zip';
         } else {
-          binaries.iedriver.url = urlPrefix + '_win32_' + versions.iedriver +
-              '.zip';
+          return urlPrefix + '_win32_' + versions.iedriver + '.zip';
         }
       }
     }
@@ -125,6 +123,18 @@ var httpGetFile = function(fileUrl, fileName, outputDir, callback) {
   });
 };
 
+/**
+ * Normalize a command across OS
+ */
+var spawnCommand = function(command, args) {
+  var win32 = process.platform === 'win32';
+  var winCommand = win32 ? 'cmd' : command;
+  var finalArgs = win32 ? ['/c'].concat(command, args) : args;
+
+  return require('child_process').spawn(winCommand, finalArgs,
+      { stdio: 'inherit' });
+};
+
 /**
  * If a new version of the file with the given url exists, download and
  * delete the old version.
@@ -197,8 +207,7 @@ switch (argv._[0]) {
        args.push('-Dwebdriver.ie.driver=' +
           path.join(argv.out_dir, executableName('IEDriverServer')));
     }
-    var javaChild = require('child_process').spawn(
-        'java', args, { stdio: 'inherit' });
+    spawnCommand('java', args);
     break;
   case 'status':
     for (name in binaries) {
@@ -232,6 +241,7 @@ switch (argv._[0]) {
     if (argv.ie) {
        downloadIfNew(binaries.ie, argv.out_dir, existingFiles,
         function(filename) {
+          var zip = new AdmZip(filename);
           // Expected contents of the zip:
           //   IEDriverServer.exe
           zip.extractAllTo(argv.out_dir);