added some classes in Common to support editing of dynamic text

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@29539 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
RichTextArea extension for web text editing

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@29540 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
starting web text editor support for dynamic text 

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@29541 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
small properties fix

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@29542 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e