Log Message:
Update contao35 to 3.5.26.

Version 3.5.26 (2017-04-20)
---------------------------

### Fixed
Prevent endless loops in the book navigation module (see #8665).

### Fixed
Limit the maximum size of dimensionless SVGs in the back end (see #8684).

### Fixed
Correctly handle custom namespaces when combining DCA files (see #8682).

### Fixed
Also check the X-Forwarded-Proto header when determining HTTPS (see #8691).

### Fixed
Correctly support 64 character template names everywhere (see #6819).

### Updated
Updated the Punycode library to version 2 (see #8693).

### Fixed
Correctly use the en dash in the calendar modules (see #8690).

### Fixed
Remove the UTF-8 BOM when combining files (see #8689).

### Fixed
Do not add the CORS headers in the install tool (see #8681).

### Fixed
Correctly move folders with an "@" in their name (see #8674).

### Fixed
Correctly redirect to the last page visited upon login (see #8632).

### Fixed
Back port the e-mail extraction improvements (see #8679).