[#57/#88] mark error window fields as optional
release 2013112501
updated generate_appcast_code script
allow partial file name matching in update_xibs.sh
[#57] improvements to error window ui

- swapped name/email and comments fields
- show error details in gray to make it less aggressive
Update XIB header version.
Add convertedAmount text field to send window.
Extract amount field setting/reading into methods.
Set converted amount when setting amount.
Remove number formatter from text field so it can be updated continously.

With an attached number formatter, reading the value would cause a re-format during typing.
Update the converted amount while typing.
Add reverse conversion.
Disable converted input for fixed amounts.
Make exchange rate API call return exchange rate as NSDecimalNumber.
Use real exchange rate for conversion.
Add a pop up button to select the conversion currency.
Store selected currency in user defaults.
Replace custom Bitcoin formatter with HICurrencyAmountFormatter.
Ensure a clean state while exchange rate request is active.
Extract currency exchange method into service.