Fixed wbxml parser issue

Was not checking for empty elements and causing parse traverse issue
Fixed wapxml: misnamed class member
Began "Sync" command response parser work

-Added Sync command response parser for "add" email collections
-Added parsers to "objects" protocol files (MSASEMAIL, MSASAIRS)
-Updated playground (pyActiveSync.py) with latest proof-of-concepts
-.gitignore changes