CiviCRM Contribution/Membership pages do not display renewal status for Lifetime Members

If a member has a lifetime membership in an organization and goes to the online contribution/membership page
the membership status is not displayed (likely any membership with no end date). We should display the status.

"Your $membershipTypeName membership does not expire (you do not need to renew this membership)."

Also fixed a bug where Cancelled memberships where displayed as if they were an existing membership.

— pushed to a separate issue: http://issues.civicrm.org/jira/browse/CRM-9001
By default, the current membership (lifetime) is pre-filled in the membership field (regular block or priceset) so that the default choice is to renew the lifetime membership

Actions?

For pricefields where the membership type is required, give a warning that lifetime membership is to be renewed and ask to continue (they contact should be using a different sign up page in this case)

For pricefields where the membership is optional, do not display the price field.