Umple textual code editor

[ElwinLiu]

• Editing of Umple code with LSP support (Johan is putting in to current system)
• All LSP features supported
• Collaboration, with indication of number of people collaborating, dynamic text update, etc.
• Full undo history for all edits (whether done by text editing or diagram)
• Ability to work with multiple Umple files (current system uses tabs)