first draft at classification methods.
fixed mv rescaling for predict.wordscores
More documentation and details on fitmodels(), predict(), and textmodel class.  Drafted textmodel_NB.
trying formula syntax for classifier
ridge regression tests
Merge branch 'dev' of https://github.com/kbenoit/quanteda into dev
Added minTotal option to trimdfm()
formula function adapted
merging formula and dfm model fitting functions
textmodel() generic and methods for models wordscores and naivebayes/NB.  print, summary, and predict methods working.  More or less.
Tweaks to print methods
weighting and smoothing functions
Merge branch 'dev'