Add initial JSON entries

[ddbeck]

This PR adds a few JSON entries for short descriptions that I've revised. I figure we'll work out how we want to layout the descriptions by revising this PR.

My initial approach was to simply dump the short descriptions into JSON files named for each CSS property. This has the benefit of easy-to-follow diffs (i.e., the list of files modified tells you which properties changed), at the expense of more files and a bit of JSON noise. Plus it was easy to do this (I've got the start of a script to write out wiki short descriptions to JSON now).

Some other approaches I considered but didn't exactly reject that might be worth considering, however:

• using different keys (e.g., wiki page URLs instead of property names)
• adding additional data (e.g., wiki page URL, a last-scraped date, etc.)
• all properties in one JSON file (pro: fewer files; con: more complicated diffs)
• all properties in a plainer format such as a CSV file or in individual .txt files (pros: simpler format, less fuss with escaping stuff; con: harder to add additional data)

This is a step toward fulfilling #5.

[ddbeck]

I do think it's a little redundant having a file, say, columns with a columns key in it. We could call it short_description perhaps? Or I wonder if we should adopt the BCD approach where every file contains the full path to the item

OK now that you've said this I think this is probably the right thing to do, instead of inventing our own structure. And since we're not planning on writing this stuff by hand, I think having more boilerplate isn't a huge problem. I pushed another commit that does this format and also fixed the missing newlines.