WIP on moving refresh to a strategy pattern
Remove SpecialEvents strategy & Events; we're going to modify updater.js
Replace calls to _queryAsJSON to _simpleQuery

This drops most instances of retrying
Rename _simpleQuery to _contentQuery

It queries the content column!
Add missing vars in catalog-remote.js
Eliminate _queryWithRetry
Drop refresh logic around constraint solver
Run updater every 15 minutes to refresh often, but don't log as often
Get rid of connectionFailed field in retval from updateServerPackageData
Remove unused _currentRefreshIsLoud
Replace catalog refresh with helper
And so move it to a refresh strategy
Tolerate catalog refresh throwing
RemoteCatalog refresh throws now
Record in strategy if package refresh failed; explain if so
Tweak the progress of package sync
Add a missing semi
release.load no longer needs buildmessage

It used to need buildmessage because catalog.official.getReleaseVersion
used to be capable of rebuilding local packages. Now it can't! Simplify
all call sites.

Note that buildmessage was not actually used to express "no such
release", before or now.
release.load can't throw OfflineError any more

So stop giving tests a way to force-throw it (might break springboard
test; fix this before merging) and stop catching it.

(release.load now just does a single sqlite query!)
drop unnecessary variable