Offline renewal of expired membership should respect "Renewal Entered Date" as the beginning of the new membership period

When renewing an expired membership, renewal logic should use 'Date Renewal Entered' instead of today to calculate the new membership end date. In Stoobs attached exampled, an expired General membership (2 year rolling) with 'Renewal Entered Date' of January 30, 2013 should have new membership end date of January 29, 2015. This date should also be the one displayed in the status message (currently a completely incorrect date is displayed).

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Reproduced on demo site when using the "More" > "Renew" link for an expired membership.

This is a very common use case. A member who is expired sends in a check and the staff renews them offline. The renewed membership end date should make some sense, either be
1. a year from their date of renewal entered OR 2. a year from the original end date. CiviCRM does neither, ignored the date renewed and sets the new end date from today.

The status message is also in not congruent with the behavior.

There can be a sizable bounty on this one we you can fix it fast and provide a patch for 4.2. Contact Stoob for $ or help. Their preferred behavior would be to set the new end date to be one length (however long that might be, usually a year) from the renewal date entered.