Scripts: added a script to change the version of libCellML.
Scripts: added a script to change the version of libCellML.

nickerso/libcellml,cellml/libcellml,cellml/libcellml,cellml/libcellml,nickerso/libcellml,nickerso/libcellml,cellml/libcellml,hsorby/libcellml,nickerso/libcellml,hsorby/libcellml,hsorby/libcellml,hsorby/libcellml