[dist] Bump version to 1.2.0
[dist] Bump version to 1.2.0

meleslilijing/director,tanzhihang/director,ks3dev/director,vitalsource/director,fadeit/director,andradedev/director,mylikes/director,webx32/director,mylikes/director,stonegithubs/director,GerHobbelt/director,meleslilijing/director,webx32/director,cpg1111/director,kiritoe/director,fadeit/director,andradedev/director,sheldonzf/director,pandoraui/director,pandoraui/director,flatiron/director,ks3dev/director,tanzhihang/director,vitalsource/director,lzhengms/director,pocketjoso/director,kiritoe/director,sheldonzf/director,GerHobbelt/director,lzhengms/director,cpg1111/director,pocketjoso/director,stonegithubs/director