axes labeling wrong for zooms deeper than 1E-8

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@23190 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
speed up drawing axis labels

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@23191 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e