v0.4.0

This is a breaking release that fixes a spelling error for an OpenURI option field and implements some more portals.

Changes:

• Rename the Writeable field in openuri.OpenURIOptions to Writable to fix spelling error.
• Implement the OpenFile and OpenDirectory functions in the OpenURI protocol.
• Implement the Trash protocol.
• Add some new helpers to the settings/appearance package to convert any values to corresponding values. Useful inside the change listener of the settings package.