Feature Request: Change Priority Levels

Hello,

Currently, the plugin seems to give all pages and posts the same change frequency and priority:

<changefreq>daily</changefreq>
<priority>0.8</priority>

However, it would really be helpful if the user could change the ‘frequency’ to something other than daily, for example monthly or yearly. But most importantly, the user should be able to determine a page’s importance by manually adjusting or changing the ‘priority’. Some pages could be a ‘0.5’ but other more authoritative pages should be ‘1.0’.

Great plugin by the way.

Thank you.