vis: Extract vis package from batmand

vis: Extract vis package from batmand

The batmand and vis sources are actually stored in two different
repositories. It therefore makes more sense to have these two packages also
split in two different OpenWrt packages. This also allows to get the vis
sources directly from the git repository.

The SVN version of vis r1439 was actually r1346. The git export of revision
r1346 is referenced by this commit.

Signed-off-by: Sven Eckelmann <[email protected]>