Allow opening/storing design documents from/in any folder

[laundmo]

Idea: Allow users to store, open, edit and save their design documents in any folder, without importing/exporting.

Requires:

• watching files for changes
• handling of missing files

Use cases:

• network storage
• USB/removable storage
• existing repository/project folder
• VCS other than git
• Editing/using in another tool/editor