Added custom AJAX headers to the AJAX POST

I saw the 1.14.11 branch of Breeze.js included the headers suggestion I made here - http://stackoverflow.com/questions/21268636/breeze-1-4-8-angular-ajax-adapter-how-to-customize-ajax-settings/21994687#21994687 - But I could not find the update to the ajax post file.
Merge pull request #8 from PWKad/patch-1

Added custom AJAX headers to the AJAX POST. Sorry I took so long.