Example Usage

[sastoudt]

For JOSS review: https://github.com/openjournals/joss-reviews/issues/1028

• [x] In the JOSS paper you mention that this package can be used to "compare contributions of predictor variables and/or correlation structure". It would be nice to have an example of this in the README.md
• [x] add example usage of partialR2() and partialR2adj() to README.md
• [ ] add example usage of communityPGLMM() to README.md
• [x] note change in binaryPGLMM() from the ape package in README.md
• [x] add example usage of different values for parameter sigma2_d in README.md

[daijiang]

@sastoudt Thanks! We have added more examples in README.md. However, we did not add example for phyr::commuintyPGLMM() because it is not stable yet. At this stage, we don't want to put phyr as a package imported or suggested by rr2, which will be required if we add examples about it in README (and add tests). We have tested the usage of rr2::R2() on phyr::commuintyPGLMM() locally. When phyr is stable in the near future, we will add examples in the README.md and tests in the test folder.