remove imports from spark_bootstrap.dart
Merge pull request #1650 from devoncarew/devoncarew_remove_imports

remove imports from spark_bootstrap.dart
Clean up spark-suggest-box/SearchOracle leftovers after recent switch to file filtering
Merge pull request #1651 from ussuri/fix-for-removed-suggest-box

Clean up spark-suggest-box/SearchOracle leftovers after recent switch to file filtering
Remove unused widget imports + some comments
Merge pull request #1653 from ussuri/remove-unused-widget-imports

Remove unused widget imports + some comments
Merge remote-tracking branch 'upstream/master' into update-to-polymer-0.10.0-pre.9
Switch from `import 'packages/'` to `import 'package:' for widgets

See related issue #500, which now seems to be fixed/required.