Refresh catalog only on relevant errors

Fixes #2846.  Fixes #2847. Fixes #2979.

Errors in the build process that could be fixed by refreshing the
catalog now cause the catalog to refresh, assuming we have not already
refreshed it recently and that we are not offline.

These commands now don't need to refresh at startup: remove, run, debug,
create, build, bundle, deploy, test-packages, rebuild, and self-test

It should be OK for create to throw SpringboardToLatestRelease even
without refreshing, since release.latestKnown is still something we know
about.
Use setImmediate instead of setTimeout for yields

It's faster and still lets IO and signals through.
Tweaks to StatusPoller

- Lower STATUS_INTERVAL_MS from 500 to 50. Note that we were effectively
  doing 150 or 100 anyway: the _pollFiber was polling every 100, and the
  nudged _throttledStatusPoll was actually throttling at the default of
  150, not 500, because the Throttled constructor was being invoked
  incorrectly (without the named 'interval' option).

- Use the same throttler for _pollFiber and nudge.
Nudge console for every compiled source file

This will refresh the status bar more often and make the build tool more
responsive to signals.

Now that yield uses setImmediate, this has minimal effect on
performance.
Upgrade esprima and escope
Don't make unnecessary cordova unibuild for app

Start on #3274.  Since we don't cache app isopacks to disk, we don't
have to worry about invalidating this.
Wrap a large number of fs calls inside files.*
Convert a few more fs calls to files.*
More moving fs.* to files
Implement read/write streams and open/read/close
Get rid of fs from auth.js
Remove fs and unused imports from catalog-local and catalog-remote
Remove unused imports from catalog.js
Replace a whole lot of fs calls
Fix error
Migrate a lot more fs. calls to files.
Add a temporary symlink method
Convert old test to files.*
Use files.pathX instead of path.x everywhere
Replace path.x to files.pathX in tests