Adds timestamp-related columns to report.xls

This PR should resolve issue #299.

The following columns have been added/tweaked in report.xls:
- ExViewed?
- ExViewedTime
- FbViewed?
- FbViewedTime?
- FbLoadCount
- PcId
- PcRegex
- FcId
- FcRegex

The timestamp and count fields are now drawn directly from the SE object, instead of by a RT query, which significantly reduces report generation times.  The report link has been re-enabled for certain user types in the development environment to allow testing of user-type-specific columns.  The link is still restricted to admins in production.

The new SE fields are populated by cron jobs which run every 30 minutes, so unless traffic is very high researchers should be getting pretty accurate results quickly.  It will take a few hours for the backlogged updates to be worked off (the cron jobs self-regulate), but after that the tasks are quite efficient.

Testing will need to cover report generation (for researchers and non-researchers), cron jobs, and feedback viewing and credit.  The full data.yml file from the live site should be loaded on the current master branch before merging the new code and running migrations.