copy row names from R to vtkTable

Since vtkTable does not have a concept of row names, we add a
vtkStringArray containing the names as the first column of the
vtkTable.

Change-Id: I2c9e20ed2c1d9cc21205e137ce9b9cfedd02a816
Merge topic 'R_row_names' into master

48341cd5 copy row names from R to vtkTable