[TASK] (vendor-preview): announce snapshot of 14. May 2015

On May 14th 2015 a snapshot was taken by

  wget -o wget.log -np -X textfiles,lectures \
    -r http://www.software-for-seismometry.de/

Display full contents of the snapshot in files
 - CONTENTS-ls-lR.txt and
 - CONTENTS-tree.txt

README.md

@@ -47,7 +47,7 @@ Contents of the current vendor snapshot are presented in
  * [CONTENTS-tree.txt](CONTENTS-tree.txt)
  * [CONTENTS-ls-lR.txt](CONTENTS-ls-lR.txt)
 
-Date of the snapshot: 18. Sep 2009
+Date of the announced snapshot: 14. May 2015
 
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