Small distributed-server-side code changes, to prep for Monday's release.

This needs to be handled immediately, so it can get into the codebase for at least a couple of days before release.

This makes two actual behavior changes, and a bunch of test changes to get tests working:
* Student coach report is expensive, but useful.  On login, forward students there--but only if they're not running on the Rasperry Pi. Note: we may want to disable it (for now) for all students, as few people will know about the `CONFIG_PACKAGE` feature.
* Hide the button to sync data from KA.  We deferred the PR for properly calculating these values, so need to hide this button until 0.10.2

Other changes:
* Tests assumed incremental changes in exercises--we changed to absolute, so fix tests to do so
* New frontend forms somehow skip over links in Firefox when using tabs.  So, update those test expectations
* Fix long-standing test bug relating to loading fixtures.