add toolchain support for multiple works

- Makefile now uses implicit rules for generating works
- each work now has its own JSON file for metadata
- orthodoxize.py now uses the JSON file for metadata
generate .dcmetadata.xml files from JSON
the "all" target is .PHONY
Call of Cthulhu is in the short stories genre
add Civil Disobedience; generate nearly all the things

markdown-file changes:
- remove metadata in markdown files (it's in .json now)

preprocessing changes:
- generate Dublin Core metadata from .json (generate-dcmetadata.py)
- move the WorkInfo object to its own module
- generate iTunesMetadata.plist from .json in orthodoxize.py
- don't remove the title pages anymore
- use jankyjson.py to get metadata from .json to pandoc
- both of these are now in the "Quikscript" genre

æsthetics:
- have a nice horizontal line between the author/title/date info and the rest of the work in HTML pages
- don't include Alegreya anymore
add Thoreau's to README.markdown