Add shared pointer declarations for FSI classes (#721)

(cherry picked from commit 2aacc77)

Author: uebian

src/chrono_swig/interface/fsi/ChFsiDefinitions.i

@@ -9,5 +9,13 @@ using namespace chrono::fsi;
 
 %}
 
+%shared_ptr(chrono::fsi::FsiBodyState)
+%shared_ptr(chrono::fsi::FsiBodyForce)
+%shared_ptr(chrono::fsi::FsiMeshState)
+%shared_ptr(chrono::fsi::FsiMeshForce)
+%shared_ptr(chrono::fsi::FsiBody)
+%shared_ptr(chrono::fsi::FsiMesh1D)
+%shared_ptr(chrono::fsi::FsiMesh2D)
+
 /* Parse the header file to generate wrappers */
 %include "../../../chrono_fsi/ChFsiDefinitions.h"