Use different login methods for web and tablet

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@35725 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
#4482 manual classes on Histogram tab. New, common Validation class.

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@35726 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e