Update to work with tidytext's cast_sparse, data_frame->tibble
- Update to work with the latest version of tidytext's cast_sparse. Adds rlang to IMPORTs. (@juliasilge, #30)
- Update from data_frame() to tibble() in examples
- Removed topicmodels from SUGGESTS (hasn't been required for several versions)
- Fixed spelling mistakes of occurence->occurrence