Log Message:
Update contao33 to 3.3.7, security release.

Version 3.3.7 (2014-11-24)
--------------------------

### Fixed
Fixed a potential directory traversal vulnerability.

### Fixed
Fixed a severe XSS vulnerability. In this context, the insert tag flags
`base64_encode` and `base64_decode` have been removed.

### Fixed
Handle nested insert tags in strip_insert_tags().

### Fixed
Correctly store the model in Dbafs::addResource() (see #7440).

### Fixed
Send the request token when toggling the visibility of an element (see #7406).

### Fixed
Always apply the IE security fix in the Environment class (see #7453).

### Fixed
Correctly handle archives being part of multiple RSS feeds (see #7398).

### Fixed
Correctly handle `0` in utf8_convert_encoding() (see #7403).

### Fixed
Send a 301 redirect to forward to the language root page (see #7420).