[toolchain] Give more spacing between nodes for beat.editor

Fixes beat.editor#132

beat/core/toolchain.py

@@ -425,9 +425,12 @@ class Toolchain(object):
         make_label = make_layout_label if is_layout else make_drawing_label
         root = Digraph(self.name)
         splineType = 'line' if is_layout else 'polyline'
+        # default is 0.25, but it seems 0.5 is needed to keep everything separated
+        # when the layout is parsed by beat.editor
+        nodesep = '0.5' if is_layout else '0.25'
         root.attr('graph', rankdir='LR', compound='true', splines=splineType,
                 labelloc='t', label=title, fontname=fontname,
-                fontsize=str(3*int(fontsize)))
+                fontsize=str(3*int(fontsize)), nodesep=nodesep)
 
         datasets = Digraph('dataset_cluster')
         datasets.attr('graph', rank='same', label='datasets')