Log Message:
Update contao35 to 3.5.12.

Version 3.5.12 (2016-04-22)
---------------------------

### Fixed
Correctly handle files with uppercase file extensions (see #8317).

Version 3.5.11 (2016-04-21)
---------------------------

### Fixed
Correctly pass the channel ID to the newsletter list template (see #8311).

### Fixed
Do not encode the database password (see #8314).

### Fixed
Fixed adding new folders in the file manager (see #8315).

Version 3.5.10 (2016-04-20)
---------------------------

### Fixed
Always trigger the "isVisibleElement" hook (see #8312).

### Fixed
Do not change all sessions when switching users (see #8158).

### Fixed
Do not allow to close fieldsets with empty required fields (see #8300).

### Fixed
Make the path related properties of the File class binary-safe (see #8295).

### Fixed
Always allow to navigate to the current month in the calendar (see #8283).

### Fixed
Correctly validate and decode IDNA e-mail addresses (see #8306).

### Fixed
Do not add the debug bar resources if `hideDebugBar` is enabled (see #8307).

### Fixed
Skip forward pages entirely in the book navigation module (see #5074).

### Fixed
Do not add the X-Priority header in the Email class (see #8298).

### Fixed
Fix an error message in the newsletter subscription module (see #7887).

### Fixed
Determine the search index checksum in a more reliable way (see #7652).