CONTENTBOX-158: Fix CKEditor Width/Alignment

It seems the "span2" class on the markup and editor drop-downs above
CKeditor are causing the issue. Changing the class to "textfield" seems
to resolve the issue, and also fixes another weird issue with the label
alignment on those fields.
Merge pull request #80 from existdissolve/development

CONTENTBOX-158: Fix CKEditor Width/Alignment