Update R&J model description

[emartinez-usgs]

Under the Model Tab section, I suggesting adding a phrase to
describe the basic point of the R&J model: "Forecasts are currently
made only with the Reasenberg-Jones (1989, 1994) model, which _____."

Okay, change to something like: "Forecasts are currently made only with the Reasenberg-Jones (1989, 1994) model, which models the aftershock rate with a smooth decay with time following the mainshock.”

[llastowka-usgs]

Jeannne said on 9/2 to hold off