Make sure Worksheet GUI has nice header too

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@26884 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Hide algebra arrow when tablet GUI hidden

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@26885 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
InputDialog: custom keys

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@26886 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e