lower-order ngrams not pruned when training with skipgrams, minlengh > 1 and t > 1

[proycon]

colibri-patternmodeller -c input.colibri.cls -f input.colibri.dat -o input.colibri.patternmodel -t 2 -l 4 -m 4 -u -s -P results in uni/bi/trigrams as well..