Merge pull request #76 from raamdev/000000-dev

Check if Login Welcome Page is set before redirecting to it.
Redirection defaults to home page.
s2member_subscr_baid
@TODO Shortcode equivalents using [else] syntax.
s2member_subscr_baid
Adding support for `txn_type=mp_cancel`.
Adding Shortcode equivalents for previously impossible tasks. Related to WebSharks/s2Member#53
Adding support for EOTs settings against Partial Refunds. Closes WebSharks/s2Member#40
Adding s2Drip examples.
Updating [s2Drip] and examples.