Add-Debugger

The script adds or replaces existing debugger in any PowerShell runspace.
It is useful for hosts with no own debuggers, e.g. Visual Studio NuGet
console ("Package Manager Host"), bare runspace host ("Default Host").
And it may be used instead of existing debuggers ("ConsoleHost").

The script is called at any moment when debugging is needed. To restore
the original debuggers, invoke Restore-Debugger defined by Add-Debugger.

For output of debug commands the script uses Out-Host or a file with a
separate console started for watching its tail.

For input the input box is used for typing PowerShell and debugger
commands. Specify the switch ReadHost for using Read-Host instead.

PowerShell commands are invoked in a child of the current scope. In order
to change current scope variables you would use `Set-Variable -Scope 1`.
But the script recognises `$var = ...` and assigns in the proper scope.