Fixed some typos in help messages.

encode.sh

@@ -5,7 +5,7 @@
 # * Progress printing
 
 if [ $# !=  "2" ] ; then
-    echo "Usage: encode input-video.format output_prefix";
+    echo "Usage: encode input-video.format output-prefix";
     exit 1;
 fi
 
@@ -17,7 +17,7 @@ fi
 
 mkdir "timings" 2> /dev/null
 if [ ! -d "timings" ] ; then
-    echo "Could not create directory: timing"
+    echo "Could not create directory: timings"
     exit 1
 fi