Event fee should be a text string in edit mode ..

We currently freeze the event fee (if a contribition record is attached) in edit mode (for a specific contact). Lets change this rule to make the fees a "view block" for all edit cases. We should reuse the "view" code from the views amount. Please test with the foll cases:

1. simple event reg
2. price set event reg
3. event reg with early bird discount
4. event reg with discount hook