Updating usage help in readme file and tidy up some character

README.md

@@ -11,13 +11,13 @@ Usage help:
         INPUT_FILE                              Name of the image to be converted.
 
     optional arguments:
-        -h, --help                              show this help message and exit
+        -h, --help                              show this help message and exit.
 
-        -r, --rotate                            Rotate image 90 degrees.
+        -r, --rotate                            Rotate image 90 degrees for more sexy spectograph looks and sound.
 
         -i, --invert                            Invert image colors.
 
-        -o OUTPUT, --output OUTPUT              Name of the output wav file. Default value: out.wav).
+        -o OUTPUT, --output OUTPUT              Name of the output wav file. Default value: out.wav.
 
         -b BOTTOM, --bottom BOTTOM              Bottom frequency range. Default value: 200.