Top-level name capitalization is not respected

When executing `npx quicktype --lang ts --just-types -t Foobar --src schema.json`, the top-level output looks like this:

`export interface FOOBAR {...}`

(This happens without the --just-types, but is easier to read with it)

You can work around this by specifying `--acronym-style original`... but I suspect this is a bug, and providing that flag might have unintended consequences beyond the top-level.