Report recipients are not notified when report fails to generate

[natanlao]

Currently, when a report fails to generate, it fails silently unless the report has failed to generate for four days. In this case, only Erich is notified. Report recipients should be notified of failures to distinguish between operator error and the absence of data.

Further, the reporting script ought to issue a partial report if data is available. This will require distinguishing between projected costs (e.g., monthly cost amortized over each day in the month) and "normal" charges.