issues on dashboard title and logo

fixes #2227
well, if someone wants to use a 3-or-more rows title he's screwed anyway
issues on dashboard title and logo

why limit title_mode: single_text to 140px anyway
Merge pull request #2244 from net02/patch-3

issues on dashboard title and logo
documentation improvements
Merge pull request #2250 from greg0ire/doc_improvements

Doc improvements
Merge remote-tracking branch 'sonata-project/master'