Fixes #542 and #543 Issues with <![CDATA[ tags

Problems in syndication.php and importing/exporting themes.
Fixes #542 #543 - issues with nesting CDATA tags

https://en.wikipedia.org/wiki/CDATA#Nesting is a better way to go about
this...
Fixes #542 #543 - issues with nesting CDATA tags

Fixes this in more locations...
Fixes #542 #543 - issues with nesting CDATA tags

Remove filter on perpage as it is stored as an integer.
Merge pull request #547 from JordanMussi/fix-542+543

Fixes #542 and #543 Issues with nesting CDATA tags