Fixed bug where Feed Maximizer option only worked when Podcast Channels was enabled

PowerPress 6.0+ will no longer be compatible with WordPress 3.0.x, 3.1.x and 3.2.x. Please upgrade to WordPress 3.3 or newer to install future versions of PowerPress.

iTunes keywords feature has been removed, feature was deprecated last year by Apple. The iTunes keywords field will appear for previous episodes that used the feature.

git-svn-id: https://plugins.svn.wordpress.org/powerpress/trunk@964799 b8457f37-d9ea-0310-8a92-e5e31aec5664