updated pry_instance.rb to use binding_stack, simplified some methods
updated pry_instance.rb to use binding_stack, simplified some methods

caporta/pry,scalixte-mdsol/pry,sferik/pry,geoffreylitt/pry,nju520/pry,jasnow/pry,josue804/debunker,pvdb/pry,ooohiroyukiooo/pry,gfvcastro/pry,85x14/pry,shockone/pry,85x14/pry,bronzdoc/pry,nju520/pry,sferik/pry,ngpestelos/pry,tdg5/pry,raeno/pry,shockone/pry,pvdb/pry,bronzdoc/pry,shockone/pry,richo/pry,nju520/pry,gfvcastro/pry,icebreaker/pry,jasnow/pry,ooohiroyukiooo/pry,scalixte-mdsol/pry,icebreaker/pry,caporta/pry,raeno/pry,ngpestelos/pry,jasonm23/pry,caporta/pry,85x14/pry,raeno/pry,josue804/debunker,jasonm23/pry,jasonm23/pry,jasnow/pry,geoffreylitt/pry,printercu/pry,tdg5/pry,sideci-sample/sideci-sample-pry,ooohiroyukiooo/pry,deivid-rodriguez/pry,scalixte-mdsol/pry,tdg5/pry,printercu/pry