Changes for R-package polytomous

Changes in version 0.1.6 (Dec 20th, 2012) (since version 0.1.4)
Implementer: Antti Arppe <antti.arppe@iki.fi>

* general modifications and fixes to several functions for
  implementing polytomous logistic regression to make the package
  compatible with the new version of the 'lme4' package

* new function 'nominal' and associated methods, new dataset
  'shanghainese', and vignette 'shanghainese' added to provide
  syntactic sugar for running multiple univariate and bivariate
  analyses of categorical variables based on 'chisq.posthoc' and
  'associations' used in Han, Arppe & Newman (forthc.)

* two functions 'extract.exemplars' and 'extract.prototypes' as well
  as vignette 'exemplars2prototypes' added to describe analyses in
  Divjak & Arppe (2013)
