Changes in 1.1.1
  * Changed maintainer email address.

Changes in 1.1.0
  * Added support for numerical differentiation, using numDeriv package.
  * Added log-density validation function, sns.check.logdensity.
  * Major revision of vignette.
  * Edited help files, including splitting of sns and sns.run.

Changes in 1.0.1
  * Added match.arg to handle "method" argument in "ess" function.
  * Revised vignette.

Changes in 1.0.0
  * Added state space partitioning to sns(), using recursion.
  * Refined sns.run() interface.
  * Refined print/summary S3 methods.
  * Added print.summary.sns, plot.sns, predict.sns, summary.predict.sns and print.summary.predict.sns methods.
  * Improved documentation, including new examples.
  * Refined ess() implementation and interface, and added logic to handle zero-variance cases.
  * Added vignette.

Changes in 0.9.1
  * Made improvements and corrected typos in the documention.
  * Fixed typo in an author name.
  * Fixed corner cases bugs in sns.run().