[BUG] - Should not create Fee Allocation record if zero dollars

[dwhitig]

I was testing to see if I could override the fee amounts at the instance level which you can - AWESOME!. I had both a fee ($30) and additional fee on the parent Summit Event ($10). On my instance event, I wanted to override the amount and charge a different fee ($15) but NO additional fee. When I tested putting nothing in the additional fee, on the registration page, the parent additional fee was added in the total charged $25 ($15 from the instance plus the $10 additional fee from the parent event). To work around this I put a zero ($0) in the additional fee field on the event instance. When I went to register, it looked great as the total fee showed $15. When I completed the registration process and then looked at the registration in Salesforce, it had an entry for the $15.00 and an entry for $0 (the zero dollar I put on the instance). If you could not write zero dollar amounts to the summit event fees table, this would give the end users the maximum amount of flexibility but not junk up the fees area with zero dollar entries.