kbenoit/quanteda: CRAN v0.9.9-17

Bug fixes and minor feature additions. Changes since v0.9.9-3 Bug fixes Fixed a bug causing dfm and tokens to break on > 10,000 documents. (#438) Fixed a bug in tokens(x, what = "character", removeSeparators = TRUE) that returned an empty string. Fixed a bug in corpus.VCorpus if the VCorpus contains a single document. (#445) Fixed a bug in dfm_compress in which the function failed on documents that contained zero feature counts. (#467) Fixed a bug in textmodel_NB that caused the class priors Pc to be refactored alphabetically instead of in the order of assignment (#471), also affecting predicted classes (#476). New features New textstat function textstat_keyness() discovers words that occur at differential rates between partitions of a dfm (using chi-squared, Fisher's exact test, and the G^2 likelihood ratio test to measure the strength of associations). Added 2017-Trump to the inaugural corpus datasets (data_corpus_inaugual and data_char_inaugural). Improved the groups argument in texts() (and in dfm() that uses this function), which will now coerce to a factor rather than requiring one. Added a dfm constructor from dfm objects, with the option of collapsing by groups. Added new arguments to sequences(): ordered and max_length, the latter to prevent memory leaks from extremely long sequences. dictionary() now accepts YAML as an input file format. dfm_lookup and tokens_lookup now accept a levels argument to determine which level of a hierarchical dictionary should be applied. Added min_nchar and max_nchar arguments to dfm_select. dictionary() can now be called on the argument of a list() without explicitly wrapping it in list(). fcm now works directly on a dfm object when context = "documents"