[DOC] Adding image directory from docs2.

git-svn-id: http://svn.seqan.de/seqan/trunk@14401 e6417c60-b987-48fd-844e-b20f0fcc1017
[DOC] Dox documentation for module seq_io.

git-svn-id: http://svn.seqan.de/seqan/trunk@14402 e6417c60-b987-48fd-844e-b20f0fcc1017