Remove `call`.
Don't even issue a warning in . Just do nothing.
Revert "Skip one more line of tracebacks in REPL."

This reverts commit 8db677b102ae68cd6db1db270c6d7e182ef5bd34.
Do not output a traceback on ^C.
Get rid of enveval.
Make the optional appearance changes even more awesome.

 * Prompts now have fixed colors.
 * Interactive console results are prefixed with "=".
 * Tracebacks are shown with more recent calls first.
 * The source code in tracebacks will be truncated if it does not fit on a single TTY line.