[sailfish-browser] Do not show empty titles from history

There is still possibility that following kind of history
entries exists:
1) www.google.fi ""
2) www.google.fi "Google"

In above case we like to show only the one that contains a title.
Unfortunately this also removes pages from history that do not
contain title at all. However, I think that it is quite rare case.
Add unit tests for empty title
Merge pull request #101 from rainemak/removeEmptyTitles

[sailfish-browser] Do not show empty titles from history