added maxiteration to BatchTrainer and ParallelBatchTrainer

default value is -1 which means "no limit" which means iterate until
optimizer detects convergence
fix bugs in sum log probe when dealing with infinite values
refactor chain model to make fast fb/viterbi more generically available
Merge pull request #146 from Craigacp/master

Fixed a missing type parameter in DiscreteSeqVar.value.
Merge pull request #148 from lvilnis/chain-tweaks

Chain tweaks
remove some unnecessary arguments from chain inference and add comments
Merge pull request #149 from lvilnis/chain-tweaks

remove some unnecessary arguments from chain inference and add comments
Merge remote-tracking branch 'origin/master' into ps
Merge pull request #150 from peschue/ps

Made maxiterations work also for BatchTrainer and ParallelBatchTrainer
Bug fixes for CollapseDigitsLemmatizer.

It thought it was a SimplifyDigitsLemmatizer (factory method created the
wrong class, and it's process method returned the wrong type).