cmdstanr v0.6.1

What's Changed

• Store return codes instead of always querying exit status by @jgabry in #798
• enable jacobian argument for optimization by @jgabry in #799
• Fix init_model_methods for models with no data by @andrjohns in #801
• Document a CmdStan-focused way to pre-compile Stan models in R packages by @wlandau in #809
• Describe how to efficiently save model fit objects by @wlandau in #816
• fix errors in doc for new methods by @jgabry in #823
• Give informative error when exposing stan functions with precompiled model by @andrjohns in #831
• Bugfixes in .stanfunctions, hessian model method, and exposing RNG functions by @andrjohns in #811
• Fix variable_skeleton() with containers by @andrjohns in #832
• Improve handling of user header by @martinmodrak in #818
• change duplicate stdout_file to stderr_file by @jgabry in #834

Full Changelog: v0.6.0...v0.6.1