Merge pull request #68 from holtgrewe/fix/nightly_builds

[FIX] Hotfix for nightly builds.
[FIX] WuManber now also works when one needle is empty.
Merge pull request #71 from holtgrewe/hotfix/find_wu_manber

[FIX] WuManber now also works when one needle is empty.
[FIX] Fixed ticket 1121, a bug in the index construction.
[FIX] Fixed ticket 1121, a bug in the index construction.