- fix bug in 'dacca' model to do with very occasional state-variable positivity violations.  The model is slightly different now, but likelihoods at MLE appear to be much the same.  This makes sense since positivity violations are extremely rare near the MLE.


git-svn-id: svn://svn.r-forge.r-project.org/svnroot/pomp@887 edb9625f-4e0d-4859-8d74-9fd3b1da38cb