SIBER 2.1.4

• fixed "vignettes with duplicate titles" warning
• added new vignette Plot-posterior-ellipses that shows how to plot multiple posterior ellipse draws on top of data using ggplot2.
• fixed fitEllipse so that it now correctly inherits parms$n.chains and parms$n.thin from input
• added ability to save the raw jags output to *.RData file to enable convergence diagnostics for each ellipse within fitEllipse. This option is set in the higher level user-specified object parms$save.output.
• added new vignette Test-convergence to illustrate this new functionality of saving the raw jags output and testing using Gelman diagnostics.