Due to some commands/tests still using the legacy "..." commands, we
can't fully remove oldshell code yet, but with this patch we just hide
it from the end users. Rzshell is now the default and only shell and
rzshell autocompletion is the default and only autocompletion engine.
* Unwrap quoted strings when passing args to newer handlers ##newshell
When a user wraps an argument, it means like in SH that he wants the
command to consider the argument as one single arg, even if composed by
multiple words. The same applies for r2newshell. So far we did not
unwrap quoted strings to maintain compatibility with old shell, but
doing this unwrapping is one of the nice feature of newshell.
* Add tests for quoting/unquoting
* Adjust tests with `w` for newshell/oldshell
