Respect the type of output (e.g. pipe, file, stdout)

[fredmorcos]

TVrank should respect the type of output and print contents accordingly. As an example, when printing out to the a terminal, colors and tables should be rendered by default as usual. But when printing to a file or a pipe, contents should be printed in a way that is in line with other UNIX utilities (one line per entry).

One example is to print out the contents in tab-separated values.