CFGetTypeID and CFBooleanGetTypeID are absent from swift-corelibs
Foundation, breaking the Linux and Windows builds. Decode r2's
JSON with a singleValueContainer cascade like R2Hex, where a JSON
boolean decodes as Bool and a number never does.
Make the REPL prompt a clickable mode toggle between JavaScript
and r2; ":", ":r2" and ":js" switch from the keyboard. Carry the
language on REPLCell and REPLResult, route r2 input through the
session disassembler, and render output as a JSInspectValue tree
for JSON commands or ANSI-parsed styled text otherwise.