chore: remove "rangy-official" from bower.json
chore: remove "rangy-official" from bower.json

avoid the injection of the following line of code in index.html, for it is not needed any more:
`<script src="bower_components/rangy-official/rangy-selectionsaverestore.js"></script>`

it closes the issue #514

juwit-team/juwit-editor,juwit-team/juwit-editor,juwit-team/juwit-editor,juwit-team/juwit-editor