Fixed: ngrams
Fixed: toTdm

Moved: Untested functions to R_NEEDFIXING

Deleted: Some files no logner used, such as ridParser.R

Added: a general new function called
segment()
that can segment on words, sentences, or paragraphs.
This sits alongside tokenize and for words, is equivalent to tokenize.  See ?segment and example(segment).
Merge branch 'dev' of https://github.com/kbenoit/quanteda into dev