Changed RewriteBase in .htaccess to BASE_URL
Pushing Ctrl to silverstripe Controllerstack an set Ctrl Response

An logged in member without permissions to view a file is getting following error: "Fatal error: Call to a member function setStatusCode() on a non-object in ...\framework\security\Security.php on line 233"
Merge pull request #2 from devOp1/master

Changed RewriteBase and error  correction
Add ability to define a 'canDownload()' method on a custom File DataExtension.

- If a FileExtension includes a canDownload() method, then use the boolean
output from that extension to determine access rights. If there are no
FileExtension objects with canDownload() set, then fallback to using the
existing canView() permission checks.

- Abstracts the permission checking working into
SecureFileController::canDownloadFile() rather than directly in handleRequest().

- Fixes bug where the Security::permissionFailure() call fails because no
SS_HTTPResponse object exists.

- Remove silverstripe/cms from composer require, add to suggests instead.