Support << and >> with negative number, issue 944
Support << and >> with negative number, issue 944

mrubyc/mrubyc,mrubyc/mrubyc,TJ-Hidetaka-Takano/mrubyc,TJ-Hidetaka-Takano/mrubyc,TJ-Hidetaka-Takano/mrubyc,TJ-Hidetaka-Takano/mrubyc