Fix for null mimetypes in os_files alter #3513

Made sure to check if a mimetype was null before array merging it.  When they are empty, use the array we would have merged with.
Merge branch 'SCHOLAR-3.x' into 3513-os_files_null_merge

Conflicts:
	openscholar/modules/os/modules/os_files/os_files.module
Merge branch 'SCHOLAR-3.x' into 3513-os_files_null_merge

Conflicts:
	openscholar/modules/os/modules/os_files/os_files.module
#4632: Add property to box forms to make them embedable.
#4632: Wireframe for the embedded markup.
#4632: New path to render widgets.
#4632: Render embed codes to page.
#4632: Javascript and css for the embed popup.
#4632: Use jqueryui dialog to handle popup behaviors.
Remove checkbox from Apps page.
so far.
using hook_menu().
fix.
Make it a "Toggle" button.
Roles 'vsite admin' and 'content editor' should be locked.
docs.
docs.
Behat tests: Toggle default/custom roles and permissions
Fix tests.
Code review.