added support for colouring th background instead of the foreground

src/main.rs

@@ -14,12 +14,6 @@ mod ascii_manipulation;
 mod output;
 mod model_rgb_ascii;
 
-//todo:
-/* custom background color, print font in white
- * --formats flag
- * --version flag
- */
-
 /// This is the main function.
 ///
 /// It drives the CLI module, calls the appropriate convert functions and directs output.
@@ -51,6 +45,10 @@ fn main() {
     if let Some(output) = cli.output {
         print_file(out, output);
     } else {
-        print_terminal(out, cli.colour, cli.grayscale);
+        if cli.background && (cli.colour || cli.grayscale) {
+            print_terminal_background(out, cli.colour, cli.grayscale);
+        } else {
+            print_terminal(out, cli.colour, cli.grayscale);
+        }
     }
 }