MINOR Implemented CMSMain->PreviewLink() (moved from LeftAndMain)

code/controllers/CMSMain.php

@@ -126,6 +126,15 @@ class CMSMain extends LeftAndMain implements CurrentPageIdentifier, PermissionPr
 		);
 	}
 	
+	/**
+	 * @return string
+	 */
+	public function PreviewLink() {
+		$record = $this->getRecord($this->currentPageID());
+		$baseLink = ($record && $record instanceof Page) ? $record->Link('?stage=Stage') : Director::absoluteBaseURL();
+		return $baseLink;
+	}
+
 	/**
 	 * Return the entire site tree as a nested set of ULs
 	 */

code/controllers/CMSPagesController.php

@@ -34,4 +34,8 @@ class CMSPagesController extends CMSMain {
 		return parent::Link($action);
 	}
 	
+	function PreviewLink() {
+		return false;
+	}
+	
 }

code/controllers/CMSSettingsController.php

@@ -10,4 +10,8 @@ class CMSSettingsController extends CMSMain {
 		return $this->RootForm();
 	}
 	
+	function PreviewLink() {
+		return false;
+	}
+	
 }