patch and citation

• bugfix in rptPoisson (thanks to devillemereuil)
• full citation added, type citation("rptR")

rptR 0.9.1

What's new:

• repeatabilities, marginal R2 and raw variances for random slope models.
• an update argument to make it easy to update bootstraps and permutations.
• a progress bar for all functions (except when run in parallel).
• several improvements and new sections in the documentation (we added explanations for parametric bootstrapping and permutation tests) as well as in the vignette.

initial CRAN release

v0.9.0

deleted second gitignore file