Move array user cleanup in getContentBlock().
Cleanup getMetaBlock() and add phpDoc.
Add include to cnMetaboxes_Render::metaboxes.

As suggested here:
https://github.com/jeremyBass/Connections/commit/2027bef7ebc4df3cba597794e51917dde0cdba8b#diff-1d16d60f017c62be882ef9c8048af4bcR530