Validation messages in UI. (Moved from LH #1)

[alloy]

When one application in a selection is invalid, add a red arrow next to the invalid application in the table view. Also add a red arrow next to the offending field in the invalid application and show an alert with explanation if the user presses that red arrow.

Also when we have this check the hostname according to the RFC before marking an application as valid: http://tools.ietf.org/html/rfc952 Or we could, if we even want and it works, add Punycode support.