Adds features to support default file descriptor redirects for the
target process:
1. A new command line flag '--redirect' and '-r' are added to specify
file redirects for the target process
2. New syntax is added to the 'restart' command to specify file
redirects.
3. Interactive instances will check if stdin/stdout and stderr are
terminals and print a helpful error message if they aren't.
Clarify that the currently supported version of the API is 2 and that
the preferred method for selecting it is sending a SetApiVersion
command after connection.
Fixes#2066
