CUL customizations of the layouts.php files

These customization were needed for the legacy themes, to mimic
the behavior of ExhibitBuilder in Omeka 1.5.3, where you had
sections with no landing page.
Initial commit new layouts: large images centered, text above or below
Change some margins and fix a few typos.
Add more CSS changes for tweak the margins.
Increase size of image for added item in Edit Page Content page

Redefine the aidth of image from 10% to auto to increase the size
of the image for an added item in the Edit Page Content page