Refactor `load` management comment

[westonruter]

Refactor load_tischendorf management command so that it is a more generic load command which then takes an argument specifying which text importer to run, for example: ./manage.py load Tischendorf-2.5. If the text is not specified, then all texts are loaded. Allow multiple texts to be specified, as well as multiple osisIDs. For example:

./manage.py load Tischendorf-2.5 greek_majority_text KJV2006 | Jude John.7

[westonruter]

paltman: this is in the works ./manage.py load_texts --works=Tischendorf,SomethingElse --books=Jude,Romans,Matthew

[westonruter]

Where should these import scripts go? In a sub-directory under management?

[westonruter]

Note that ideally the importers should be able to import based on an osisID which is more granular than just the book level, e.g. it is useful to be able to import just John 7. Actually, an osisRef might even be better, e.g. --osisRefs=John.7-John.8; but this is something that can be done later.