Add prefixe 'g_' to global variables in mert/evaluator.cpp
Add prefixe 'g_' to global variables in mert/evaluator.cpp

While the size of mert/evaluator.cpp is still relatively small,
adding the marker to the variables allows us to easily distinguish
them from local variables.

tofula/mosesdecoder,hychyc07/mosesdecoder,alvations/mosesdecoder,moses-smt/mosesdecoder,KonceptGeek/mosesdecoder,KonceptGeek/mosesdecoder,emjotde/mosesdecoder_nmt,alvations/mosesdecoder,KonceptGeek/mosesdecoder,moses-smt/mosesdecoder,tofula/mosesdecoder,tofula/mosesdecoder,tofula/mosesdecoder,alvations/mosesdecoder,tofula/mosesdecoder,pjwilliams/mosesdecoder,emjotde/mosesdecoder_nmt,hychyc07/mosesdecoder,tofula/mosesdecoder,pjwilliams/mosesdecoder,emjotde/mosesdecoder_nmt,pjwilliams/mosesdecoder,tofula/mosesdecoder,alvations/mosesdecoder,moses-smt/mosesdecoder,KonceptGeek/mosesdecoder,emjotde/mosesdecoder_nmt,alvations/mosesdecoder,tofula/mosesdecoder,moses-smt/mosesdecoder,KonceptGeek/mosesdecoder,KonceptGeek/mosesdecoder,hychyc07/mosesdecoder,hychyc07/mosesdecoder,alvations/mosesdecoder,tofula/mosesdecoder,tofula/mosesdecoder,pjwilliams/mosesdecoder,pjwilliams/mosesdecoder,emjotde/mosesdecoder_nmt,KonceptGeek/mosesdecoder,emjotde/mosesdecoder_nmt,pjwilliams/mosesdecoder,hychyc07/mosesdecoder,alvations/mosesdecoder,emjotde/mosesdecoder_nmt,tofula/mosesdecoder,moses-smt/mosesdecoder,alvations/mosesdecoder,hychyc07/mosesdecoder,pjwilliams/mosesdecoder,KonceptGeek/mosesdecoder,alvations/mosesdecoder,emjotde/mosesdecoder_nmt,KonceptGeek/mosesdecoder,pjwilliams/mosesdecoder,hychyc07/mosesdecoder,moses-smt/mosesdecoder,emjotde/mosesdecoder_nmt,KonceptGeek/mosesdecoder,moses-smt/mosesdecoder,moses-smt/mosesdecoder,hychyc07/mosesdecoder,moses-smt/mosesdecoder,moses-smt/mosesdecoder,hychyc07/mosesdecoder,hychyc07/mosesdecoder,moses-smt/mosesdecoder,alvations/mosesdecoder,pjwilliams/mosesdecoder,pjwilliams/mosesdecoder,emjotde/mosesdecoder_nmt,alvations/mosesdecoder