v0.18.2

Fix:

• Let toastr escape contents to prevent XSS issues.

Developer notes:

• content._unwrap() does not exists anymore: now you have to use content._plainObject().
• content._plainObject(object) can be used to replace the content with a previously exported content.

Then more fixes a few regressions/bugs introduced in 0.18.0/0.18.1!

Fix:

• Fix image dropzones #643
• Fix undo/redo and editing with adding/removing blocks and undoing the action #641
• Prevent template flickering on block variant changes (introduced with image preloading)