Merge pull request #226 from OmniaGM/fix-placholder

show placeholder if you have only an empty blockquote
fix https://github.com/daviferreira/medium-editor/issues/227
Merge branch 'master' of github.com:daviferreira/medium-editor into sw-master
Merge branch 'master' of github.com:SalamWorld/medium-editor into sw-master
merge
merge
Merge pull request #16 from OmniaGM/sw-master

link validation