consolidate where config property checking occurs
verify archive config earlier
verify index config earlier
Create Config object to cleanse incoming options
Use Config object for validating Feed options
Feed no longer needs to do any option-validating or logging
tweak what Config returns for invalid keys
Config#forArchive
Factory validates config and builds Feeds
Use new Factory and updated Config to create Feed
Factory validates/creates Archives
Config#forArchive
Factory creates Archive with Layout
use spies for Factory constructors
Config#forIndex
Factory::indexFrom
Use Config and Factory for Index
use a single NullHtml
reorder
Config#forPages