Update tagmanager.js

use jQuery.map() instead of native JS map() to make this work in IE8 (pure JS map is JS 1.6 but IE8 only supports JS 1.5)
Merge pull request #163 from apperception/patch-1

use jQuery.map() instead of native JS map() to make this work in IE8 (pure JS map is JS 1.6 but IE8 only supports JS 1.5)