Part: TopoShapePy: made Solid constructor accept CompSolid

Part.Solid(shape) now accepts compsolid as input, and creates a solid by
joining the compsolid.

Same done to Part.makeSolid().

+ change exception handling to expose the error message.

src/Mod/Part/App/TopoShapeSolidPy.xml

@@ -12,7 +12,7 @@
       Constructor="true">
 	  <Documentation>
       <Author Licence="LGPL" Name="Juergen Riegel" EMail="Juergen.Riegel@web.de" />
-      <UserDocu>Create a solid out of the shells of a shape</UserDocu>
+      <UserDocu>Part.Solid(shape): Create a solid out of shells of shape. If shape is a compsolid, the overall volume solid is created.</UserDocu>
     </Documentation>
     <Attribute Name="Mass" ReadOnly="true">
       <Documentation>
@@ -101,4 +101,4 @@ solid.offsetFaces((solid.Faces[0],solid.Faces[1]), 1.5)
       </Documentation>
     </Methode>
   </PythonExport>
-</GenerateModel>
+</GenerateModel>