CRAN Release 0.3

• Add docusaurus site
• udpipe_download_model gains and extra argument called udpipe_model_repo to allow to download models mainly released under CC-BY-SA from https://github.com/bnosac/udpipe.models.ud
• Add udpipe_accuracy
• Add dtm_rbind and dtm_cbind
• Add udpipe_read_conllu to simplify creating wordvectors
• Allow to provide several fields in document_term_frequencies to easily allow to include bigrams/trigrams/... for topic modelling purposes e.g. alongside the textrank package or alongside collocation
• Adding Serbian + Afrikaans
• Fixing UBSAN messages (misaligned addresses)
• If user has R version < 3.3.0, use own startsWith function instead of base::startsWith