Add IDs to full.json

IDs are basically filenames without `.json`. Devs can use them to navigate to the real files. The flow would be then:

1. Get full.json, i. e. [via RawGit](https://github.com/eddie/wkindex/wiki/API).
2. Locate the apps they would want to use/display/update regularly and save their IDs.
3. Next time they want to update info, they just grab the file they want from `scripts/`.