Jsoneditor

- Implemented selection API: `onSelectionChanged`, `onTextSelectionChanged`,
`getSelection`, `getTextSelection`, `setSelection`, `setTextSelection`,
and `getNodesByRange`. Thanks meirotstein.

- Fixed absolute path of css image `jsoneditor-icons.svg`, which could.
give issues with webpack plugin "file-loader". Thanks landru29.

- Implemented support for translations. Thanks mariohmol.
- Fixed a bug sometimes occurring when dragging items from array to
object, see 509. Thanks 43081j.
- Fixed autocomplete not accepting returned `null` values, see 512.
Thanks 43081j.
- Fixed memory inefficiency when working with large JSON Schema's
generating many errors. Thanks 43081j.

- Fixed a positioning issue with JSON Schema errors in text/code mode.

- Fixed view mode opening links in a new tab instead of current tab
when Ctrl key is not down. Thanks LEW21.
- Fixed 502: code editor not showing a monospaced font some cases.

- Fixed another occurrence of 494: properties not escaped in the
navigation bar.