stochvolTMB 0.2.0

Added predict function that makes it possible to simulate future volatility and log-returns.
plot has a new forecast argument that makes it possible to include forecasted volatility.
The degrees of freedom for the t model is estimated on log scale and shifted by 2 so that it is guaranteed to be greater than 2. This is to ensure that the variance is finite.
Changed parameter names from phi_logit and rho_logit to logit_phi and logit_rho to be consistent with other parameter names.
Updated README.
Updated documentation.

stochvolTMB 0.1.2