Interactive Scripting Improvements Tracking Issue

[iwillspeak]

Our current REPL leaves a little to be desired. It would be nice if we had a better embeddable scripting API in the compiler so state could be carried across from one evaluation to the next.

• [ ] Multi-statement support in the REPL.
• [ ] Dotnet interactive support.
• [ ] #!r and #!nuget
• [ ] -e, --exec immediate script mode
• [ ] -s, --script script execute mode
• [ ] Syntax highlighting in the REPL