- Logs an error message when missing files are encountered.

- Fixes problems with asset pipeline.

This fixes a bug where feedback email message is sent with multiple reply-to
addresses when (1) sender email address was supplied via the feedback form and
(2) override_from is configured in config.ini > Mail.

- Loads the facet data on demand asynchronously, potentially improving performance.

This reverts commit 1070d1ab.