implementing issue 28. commit before test on dev1 server. (13)

28) add share icons to api_gift (one icon for each api provider)
    todo: add ajax spinner while fetching share url from server. Normally quick, but server is slow and small.
    todo: check http://developer.sharethis.com/Web_Share_API
    todo: make LOV readonly while fetching link from server
    todo: change LOV blank to default after fetching link from server