volume level

git-svn-id: https://plugins.svn.wordpress.org/radio-forge/trunk@984354 b8457f37-d9ea-0310-8a92-e5e31aec5664
default volume

git-svn-id: https://plugins.svn.wordpress.org/radio-forge/trunk@984356 b8457f37-d9ea-0310-8a92-e5e31aec5664
zero volume

git-svn-id: https://plugins.svn.wordpress.org/radio-forge/trunk@984359 b8457f37-d9ea-0310-8a92-e5e31aec5664