improve appearance for compound descriptors radar chart

the radar chart remains at a reasonable size even if the viewport
is resized.

ippisite/ippidb/templates/base.html

@@ -126,7 +126,8 @@
                                                         return label;
                                                     }
                                                 }
-                                            }
+                                            },
+                                            maintainAspectRatio: false
                 }});
             };
             var drawCompoundsBiplotChart = function(canvasId, compoundId, compoundFamily, plotData, tabHash){