Event Price Set Fields - Provide a way to get event-level counts for each price field

1. Review the current data model for storing price set option values - and figure out how we can store multiple options with the same price (e.g. option_value.value) for the same price set field.

See http://forum.civicrm.org/index.php/topic,3048.0/topicseen.html for an example of the issue.

2. Folks using price sets need a way to output "counts" / "selected option" from their price set fields such that they can get totals. Currently, we export these as delimited values in a single column in export rows - which makes it difficult / impossible to calculate totals - e.g. 'How many participants have paid for the dinner option?' (how many dinners do i need to order). We have the data nicely structured in civicrm_line_item - but we need to give folks a way to get at it.