Changed server termination code for CoreNLP. Make server a singleton object by default, with the number of UDF threads mapping to CoreNLP's default thread count
Changed server termination code for CoreNLP. Make server a singleton object by default, with the number of UDF threads mapping to CoreNLP's default thread count

HazyResearch/snorkel,jasontlam/snorkel,HazyResearch/snorkel,jasontlam/snorkel,HazyResearch/snorkel,jasontlam/snorkel