support regeneration

- fix speaker
- prune empty chapters
- force regeneration of html or audio files
treat cli as more of a black box

Happy with these new changes.

- test inputs and outputs not local hashes/variables
- always load_from_cache
- PageDb initializer no longer creates database
- expose spider#outstanding, multi_site
support --content tag

- provide max paragraphs
- default content and follow css paths
- update chapter to have hash intializer