Added a function to get a CoordFrame from a CoordGroup:

CoordFrame CoordGroup::GetFrame2
And an export to python

modules/mol/base/pymod/export_coord_group.cc

@@ -48,6 +48,7 @@ void export_CoordGroup()
     .def("IsValid",&CoordGroupHandle::IsValid)
     .def("GetEntity",&CoordGroupHandle::GetEntity)
     .def("GetAtomCount",&CoordGroupHandle::GetAtomCount)
+    .def("GetFrame",&CoordGroupHandle::GetFrame2)
     .def("AddFrames", &CoordGroupHandle::AddFrames)
     .def("AddFrame", add_frame1)
     .def("AddFrame", add_frame2)

modules/mol/base/src/coord_group.cc

@@ -152,7 +152,13 @@ CoordFramePtr CoordGroupHandle::GetFrame(uint frame) const
   this->CheckValidity();
   return source_->GetFrame(frame);
 }
-  
+
+CoordFrame CoordGroupHandle::GetFrame2(uint frame)
+{
+  this->CheckValidity();
+  return *(source_->GetFrame(frame));
+}
+
 AtomHandleList CoordGroupHandle::GetAtomList() const
 {
   this->CheckValidity();

modules/mol/base/src/coord_group.hh

@@ -86,6 +86,7 @@ public:
   
   AtomHandleList GetAtomList() const;
   CoordFramePtr GetFrame(uint frame) const;
+  CoordFrame GetFrame2(uint frame);
   
   /// \brief return a filtered coord group, containing only the atoms in the 
   ///     view