Debug Dispersion measurement and added first support for XTCAV stabilizer

interface/save.py

@@ -154,6 +154,8 @@ def writeAnalysis(hid,data,scanrun=1):
 
 def writeFigure(filename,figs):
     for i,ele in enumerate(figs):
+        if ele == None:
+            continue
         plotname='%s_Fig%d.png' % (filename,(i+1))
         im = Image.open(ele)
         im.save(plotname)