get platform default value from current platform
enable platform-free packaging (keyword: all)
Merge remote-tracking branch 'upstream/develop' into package_kalite
add methods for removing data cruft

Conflicts:
	kalite/main/management/commands/package_for_download.py
don't need these packages
Merge branch 'package_kalite' into IDOC_demo
Merge branch 'remove_data_cruft' into IDOC_demo

Conflicts:
	kalite/static/data/nodecache.json
	kalite/static/data/topics.json
	kalite/utils/topics.py
Merge branch 'IDOC_demo' of github.com:bcipolli/ka-lite into IDOC_demo