Issues collection for REPL

[alexanderpann]

This issue collects issues for org.iets3.expr.repl. The language is not very polished at the moment.

• [ ] Should the REPL really be used in the editor? Would a tool be a better solution? What about creating it with an action in a temporary model?
• [ ] Can the REPL be integrated into the MPS console?
• [ ] The buttons such as Add Entry are way too small and the text is truncated.
• [ ] The entries shouldn't have a light gray background. You can't read the orange and also not the dark gray text. To separate the entries, a border could be used.
• [ ] The tooltip of ReplEntryRefand DefaultEntry is broken.
• [ ] Real collapsible cells would look better than the ones of the MPS-Extensions language.
• [ ] The checkboxes downstream updates and show diffs are not self-explanatory.
• [ ] The action Open REPL for node needs to be added to a menu such as the Language Debug or Edit main menu.
• [ ] Shortcuts for actions such as evaluating the current entry are needed.
• [ ] There is no feedback when the interpreter fails.