Fixes pipeline for FreqDist worker

This worker depends on Tokenizer, not PalavrasRaw. Before this patch FreqDist
would never run for a text in English or in a system that does not have
Palavras.
Merge pull request #109 from flavioamieiro/fix/pipeline_for_non_pt_text

Fixes pipeline for FreqDist worker
Adds wordcloud worker to the default pipeline
Merge pull request #111 from flavioamieiro/feature/wordcloud_worker

Adds wordcloud worker to the default pipeline