Jsoneditor

- Implemented support for customizing the query language used in the
Transform modal. New options `createQuery`, `executeQuery`, and
`queryDescription` are available for this now. An example is available
in `examples/23_custom_query_language.html`. See 857, 871.
- Implement undo/redo buttons in `code` mode.
- Fix history (undo/redo) being cleared in mode `code` and `text` after
transforming or sorting.

- Fix `console.log` in production code. Oopsie.

- Added CSS classes `jsoneditor-expanded` and `jsoneditor-collapsed` on array
and object nodes reflecting there state.

- Update dependency `ajv` to `v6.11.0`.
- Fix 790: editor breaking when missing a translation containing a
placeholder.

- Make it easy to create custom styling by overriding default SASS variable
values, see 881. Thanks petermanders89.
- Update `ace` to `v1.4.8`.

- Fix 873: buttons Format, Compact, and Repair not supporting
internationalization.
- Fix 877: Some CSS styling issues when used in combination with Materialize.
- Updated dependency `vanilla-picker` to `v2.10.1`.