Update usage output to show new options

gifgen

@@ -7,16 +7,15 @@ show_help() {
   echo "Usage: gifgen [options]"
   echo
   echo "Options:"
-  echo "  -i   Input file"
   echo "  -o   Output file [input.gif]"
   echo "  -f   Frames per second [10]"
   echo "  -s   Optimize for static background"
   echo "  -v   Display verbose output from ffmpeg"
   echo
   echo "Examples:"
-  echo "  $ gifgen -i screencap.mp4"
+  echo "  $ gifgen video.mp4"
-  echo "  $ gifgen -i SCM_1457.mov -o demo.gif"
+  echo "  $ gifgen -o demo.gif SCM_1457.mp4"
-  echo "  $ gifgen -i screencap.mp4 -f 15"
+  echo "  $ gifgen -sf 15 screencap.mov"
 }
 
 # Setup defaults