*7846* updated locale, languagetoggle plugin
*7846* updated German locale
Merge pull request #172 from mtub/20140430-de-locale

minor updates to de_DE locale
Merge pull request #173 from ppv1979/ojs-stable-2_4

fixed ru_RU translation + fix typos and duplicates in en_US locale
Manual merge of @mtub pull request #159
Manual merge of @mtub pull request  #151
fix dataverse xml schema validation issues
Merge pull request #174 from axfelix/ojs-stable-2_4

fix dataverse xml schema validation issues
*7846* removed extra line
*7846* removed duplicate entries from last merge
Merge pull request #175 from mtub/20140430-de-locale

minor updates to de_DE locale
Add XML validation to travis
Submodule track