Fix DAWN view for barrel calorimeter support

It seems DAWN cannot correctly handle the boolean volumes from TGeo. For example, it will draw all separate volumes that are merged by UnionSolid.

The original implementation of the support utilized UnionSolid to merge many overlapping solids. This caused unexpected behavior of DAWN, which generated incorrect views without several subdetectors.

This MR fixed the issue by re-implementing the support with only minimal uses of boolean volumes.

compact/ecal_barrel_interlayers.xml

 <lccdd>
 
     <display>
-    <vis name="EcalBarrelEnvelope_vis" alpha="0.9" r="0.99" g="0.5" b="0" showDaughters="true" visible="false" />
-    <vis name="EcalBarrelStave_vis"    alpha="0.9" r="0.99" g="0.5" b="0" showDaughters="true" visible="false" />
+    <vis name="EcalBarrelEnvelope_vis"   alpha="0.9" r="0.99" g="0.5" b="0" showDaughters="true" visible="false" />
+    <vis name="EcalBarrelStave_vis"      alpha="0.9" r="0.99" g="0.5" b="0" showDaughters="true" visible="false" />
+    <vis name="EcalBarrelFiberLayer_vis" alpha="0.9" r="0.1" g="0.5" b="0.5" showDaughters="false" visible="true" />
     </display>
   <define>
     <comment>
@@ -85,7 +86,6 @@
       <dimensions numsides="EcalBarrel_ModRepeat"
         rmin="EcalBarrel_rmin"
         z="EcalBarrel_length"/>
-      <staves vis="EcalBarrelStave_vis"/>
       <layer repeat="EcalBarrelImagingLayers_num" vis="AnlBlue"
         space_between="EcalBarrel_ScFiLayerThickness + EcalBarrel_SpaceBetween"
         space_before="0.*cm">
@@ -115,18 +115,16 @@
         rmin="EcalBarrel_rmin"
         z="EcalBarrel_length"/>
       <staves vis="EcalBarrelStave_vis">
-        <support inside="true"  material="Steel235" vis="AnlOrange"
-          thickness="EcalBarrel_Support_thickness"
-          n_beams="3" grid_size="25.0*cm" >
+        <support material="Steel235" vis="AnlOrange" n_beams="3" grid_size="25.0*cm"
+          thickness="EcalBarrel_Support_thickness" beam_thickness="EcalBarrel_Support_thickness/4" >
         </support>
       </staves>
       <layer repeat="EcalBarrelImagingLayers_num-1" vis="AnlBlue"
        space_between="EcalBarrel_ImagingLayerThickness + EcalBarrel_SpaceBetween"
        space_before="EcalBarrel_ImagingLayerThickness + EcalBarrel_SpaceBetween/2.">
-        <slice material="Lead" thickness="EcalBarrel_RadiatorThickness" vis="EcalBarrelFibersVis">
+        <slice material="Lead" thickness="EcalBarrel_RadiatorThickness" vis="EcalBarrelFiberLayer_vis">
           <fiber material="PlasticScint"
             sensitive="yes"
-            vis="EcalBarrelFiberVis"
             radius="EcalBarrel_FiberRadius"
             spacing_x="EcalBarrel_FiberXSpacing"
             spacing_z="EcalBarrel_FiberZSpacing"/>
@@ -138,14 +136,12 @@
           space_before="EcalBarrel_ImagingLayerThickness + EcalBarrel_SpaceBetween">
         <slice material="Lead"
           thickness="EcalBarrel_FiberLayerThickness/EcalBarrel_FiberChunkLayers_num"
-          vis="EcalBarrelFiberLayerVis">
+          vis="EcalBarrelFiberLayer_vis">
           <fiber material="PlasticScint"
             sensitive="yes"
-            vis="EcalBarrelFiberVis"
             radius="EcalBarrel_FiberRadius"
             spacing_x="EcalBarrel_FiberXSpacing"
-            spacing_z="EcalBarrel_FiberZSpacing">
-          </fiber>
+            spacing_z="EcalBarrel_FiberZSpacing"/>
         </slice>
       </layer>
     </detector>