More menu manager fixes if a menu set contains Zenpage CMS items but the plugin is disabled: Backend shows a note now and front end ignores them (prints empty list entries actually) until the menu is modified or Zenpage re-enabled.
GD actually supports the quite different WBMP format and not BMP.
Merge remote-tracking branch 'upstream/master' into upstream

Conflicts:
	zp-core/zp-extensions/menu_manager.php
	zp-core/zp-extensions/menu_manager/menu_manager-admin-functions.php

	modified:   zp-core/full-image.php
	modified:   zp-core/i.php
	modified:   zp-core/lib-GD.php
	modified:   zp-core/zp-extensions/menu_manager/menu_manager-admin-functions.php
	modified:   zp-core/zp-extensions/xmpMetadata.php
surpress invalid menu items
Merge pull request #123 from sbillard/master

upstream merge