Handle subprocess returning bytes (#1014220)
    
    The subprocess module returns bytes in Python 3,
    so we need to (try) decoding the output (as utf-8)
    for functions that expect text string output and
    there is now a execWithCaptureBinary for forwarding
    binary output when running commands.
    
    We also need to make sure that the output is "printable"
    when binary output logging to the program.log is enabled.