Don't use String#replace and String#split during TokenInfoDictionaryLookup

They are slow since they use regular expression and need to compile Pattern every time.
Made it possible to specify penalty parameters for search mode.

* Also fixed NPE where it always throws NPE when search mode is used due to null ViterbiBuilder.
Merge pull request #4 from masaruh/custom-penaly-parameters

Made it possible to specify penalty parameters for search mode.
Merge pull request #3 from masaruh/no-string-replace-split

Don't use String#replace and String#split during TokenInfoDictionaryLook...
Update change history, contributors and other minor changes