[WIP] Move JSON/XML modules to separate projects

[mielientiev]

The main goal of this PR is to move JSON/XML modules to separate projects.

• [x] remove Data module dependency from JSON modules
• [x] remove Data module dependency from XML modules
• [ ] do cleanup
• [ ] fix most common XML/JSON bugs
  • [x] XML: https://github.com/propensive/rapture/issues/262
  • [x] XML: https://github.com/propensive/rapture/issues/263
  • [ ] XML: https://github.com/propensive/rapture/issues/264
  • [ ] XML: https://github.com/propensive/rapture/issues/253
  • [ ] XML: https://github.com/propensive/rapture/issues/250
  • [ ] XML: https://github.com/propensive/rapture/issues/247
  • [ ] XML/JSON: https://github.com/propensive/rapture/issues/238
• [ ] add more XML/JSON unit tests
• [ ] switch to contextual
• [ ] Move JSON/XML modules to separate repos

[mielientiev]

@propensive Yep. For now, it's just copy-pasting from data module to json/xml module. In future, all json/xml modules will only depend on rapture-core. after I've done the same thing with Rapture XML, we can move Rapture JSON & XML to the separate repos

[propensive]

I'm going to tidy up Rapture, and keep track of this in Xylophone from now on.