v0.18.0

New:

• Declare accept format (images) for input files #586
• Preliminary support for data-ko-height (vertical resizer)
• Slider+Spinner widget for integer values
• New arabian language file + update many language files
• Improved conditional comments handing/replacement
• Image preloading: client side placeholders + replace images only when they are fully loaded

Developer notes:

• Many dependencies/build system updates
• Fix main source map generation
• Moved tinymce to devDependency
• Rewrote development backend to remove jquery-file-upload-middleware
• Added support for knockout 3.5.0 and 3.5.1
• Refactored undo/redo handing for "move" actions
• Bumped build requirements to Node 8 and Npm 8.3: build works with older npm but they don't correctly handle package overrides.