Added the 'title' and 'subtitle' arguments to the pcs.corr_plot user function.
This problem was detected by the new Pcs.test_corr_plot system test. The pcs.corr_plot user function now matches the rdc.corr_plot user function in terms of arguments.
Authored by: bugman 2015-03-03
Parent: [r27764]
Child: [r27766]
