Added documentation for n-grams, skip n-grams, and regex
Added codecov and appveyor
Added tidiers for LDA objects from topicmodels and a vignette on topic modeling
Added function to calculate tf-idf of a tidy text dataset and a tf-idf vignette
Fixed a bug when tidying by line/sentence/paragraph/regex and there are multiple non-text columns
Fixed a bug when unnesting using n-grams and skip n-grams (entire text was not being collapsed)
Added ability to pass a (custom tokenizing) function to token. Also added a collapse argument that makes the choice whether to combine lines before tokenizing explicit.
Changed tidy.dictionary to return a tbl_df rather than a data.frame
Updated cast_sparse to work with dplyr 0.5.0
Deprecated the pair_count function, which has been moved to pairwise_count in the widyr package. This will be removed entirely in a future version
