FEM: GMSH mesh tool, add command and add it to tool bar and make a menu entry

src/Mod/Fem/InitGui.py

@@ -49,6 +49,7 @@ class FemWorkbench (Workbench):
         import _CommandRunSolver
         import _CommandPurgeResults
         import _CommandControlSolver
+        import _CommandMeshGmshFromShape
         import _CommandMeshNetgenFromShape
         import _CommandAnalysis
         import _CommandShellThickness