Generalized options handling

1. New format for options.txt that consolidates editing metadata
(label, name, datatype, tooltip), removes runtime data
2. Generalized passing of options into Javascript, as an "sd" object.
Helper function for populating this object in ospi.py
3. Converted "loc" into a standard, editable option, added
"station_name_length" option (non-editable).
4. Added "name" as an editable option, displayed on home page.
5. Misc related code simplifications (esp in options save logic)
6. Misc unrelated minor improvements.
Merge pull request #10 from jonathan-marsh/master

Generalized options handling