Log Message:
Update contao42 to 4.2.4.  This is a leaf package.

### 4.2.4 (2016-09-21)

 * Handle special character passwords in the "close account" module \ 
(see contao/core#8455).
 * Handle broken SVG files in the Image and File class (see contao/core#8470).
 * Reduce the maximum field length by the file extension length (see \ 
contao/core#8472).
 * Fall back to the field name if there is no label (see contao/core#8461).
 * Do not assume NULL by default for binary fields (see contao/core#8477).
 * Correctly render the diff view if not the latest version is active (see \ 
contao/core#8481).
 * Update the list of countries and languages (see contao/core#8453).
 * Correctly set up the MooTools CDN URL (see contao/core#8458).
 * Also check the URL length when determining the search URL (see contao/core#8460).
 * Only regenerate the session ID upon login.