make back button go back in history if we lack history
make back button go back in history if we lack history

mozilla/zamboni,mozilla/olympia,wagnerand/addons-server,clouserw/zamboni,ddurst/zamboni,koehlermichael/olympia,ingenioustechie/zamboni,magopian/olympia,andymckay/addons-server,wagnerand/zamboni,kmaglione/olympia,kumar303/addons-server,yfdyh000/olympia,johancz/olympia,mozilla/olympia,lavish205/olympia,Nolski/olympia,eviljeff/olympia,mozilla/zamboni,jasonthomas/zamboni,robhudson/zamboni,mstriemer/addons-server,beni55/olympia,tsl143/zamboni,eviljeff/zamboni,wagnerand/addons-server,shahbaz17/zamboni,shahbaz17/zamboni,muffinresearch/olympia,Joergen/zamboni,luckylavish/zamboni,kumar303/zamboni,mudithkr/zamboni,tsl143/addons-server,diox/zamboni,eviljeff/zamboni,wagnerand/olympia,Witia1/olympia,kumar303/zamboni,jasonthomas/zamboni,ddurst/zamboni,robhudson/zamboni,elysium001/zamboni,mudithkr/zamboni,ayushagrawal288/zamboni,mozilla/zamboni,diox/zamboni,mdaif/olympia,andymckay/olympia,Hitechverma/zamboni,yfdyh000/olympia,jasonthomas/zamboni,Nolski/olympia,atiqueahmedziad/addons-server,crdoconnor/olympia,crdoconnor/olympia,Hitechverma/zamboni,mstriemer/addons-server,johancz/olympia,washort/zamboni,Jobava/zamboni,andymckay/zamboni,SuriyaaKudoIsc/olympia,mudithkr/zamboni,mrrrgn/olympia,Joergen/olympia,magopian/olympia,Witia1/olympia,robhudson/zamboni,mstriemer/zamboni,lavish205/olympia,anaran/olympia,anaran/olympia,Joergen/olympia,muffinresearch/olympia,eviljeff/zamboni,bqbn/addons-server,beni55/olympia,muffinresearch/olympia,bqbn/addons-server,Revanth47/addons-server,mdaif/olympia,mozilla/addons-server,atiqueahmedziad/addons-server,jpetto/olympia,ngokevin/zamboni,tsl143/zamboni,SuriyaaKudoIsc/olympia,Witia1/olympia,muffinresearch/addons-server,andymckay/olympia,Witia1/olympia,harry-7/addons-server,ingenioustechie/zamboni,elysium001/zamboni,psiinon/addons-server,beni55/olympia,spasovski/zamboni,kumar303/zamboni,ingenioustechie/zamboni,Revanth47/addons-server,mstriemer/zamboni,washort/zamboni,luckylavish/zamboni,elysium001/zamboni,kumar303/olympia,aviarypl/mozilla-l10n-addons-server,anaran/olympia,mozilla/olympia,Revanth47/addons-server,Joergen/zamboni,ngokevin/zamboni,harry-7/addons-server,koehlermichael/olympia,harikishen/addons-server,Nolski/olympia,harikishen/addons-server,mozilla/olympia,Prashant-Surya/addons-server,luckylavish/zamboni,kmaglione/olympia,magopian/olympia,wagnerand/zamboni,Joergen/olympia,spasovski/zamboni,koehlermichael/olympia,elysium001/zamboni,wagnerand/olympia,spasovski/zamboni,clouserw/zamboni,wagnerand/olympia,mozilla/addons-server,johancz/olympia,andymckay/addons-server,clouserw/zamboni,lavish205/olympia,wagnerand/addons-server,tsl143/addons-server,kmaglione/olympia,mozilla/addons-server,aviarypl/mozilla-l10n-addons-server,kumar303/olympia,SuriyaaKudoIsc/olympia,johancz/olympia,andymckay/addons-server,magopian/olympia,beni55/olympia,diox/olympia,tsl143/addons-server,koehlermichael/olympia,muffinresearch/addons-server,washort/zamboni,Joergen/olympia,andymckay/addons-server,kumar303/addons-server,ayushagrawal288/zamboni,Prashant-Surya/addons-server,crdoconnor/olympia,lavish205/olympia,shahbaz17/zamboni,mdaif/olympia,Joergen/zamboni,mstriemer/addons-server,mrrrgn/olympia,mstriemer/olympia,SuriyaaKudoIsc/olympia,Joergen/zamboni,bqbn/addons-server,tsl143/addons-server,diox/olympia,andymckay/olympia,eviljeff/zamboni,Hitechverma/zamboni,mrrrgn/olympia,wagnerand/zamboni,ngokevin/zamboni,ayushagrawal288/zamboni,Joergen/olympia,jpetto/olympia,Jobava/zamboni,wagnerand/addons-server,crdoconnor/olympia,kumar303/olympia,aviarypl/mozilla-l10n-addons-server,luckylavish/zamboni,Revanth47/addons-server,muffinresearch/addons-server,jasonthomas/zamboni,jamesthechamp/zamboni,mozilla/zamboni,yfdyh000/olympia,kmaglione/olympia,mstriemer/zamboni,Jobava/zamboni,ddurst/zamboni,mudithkr/zamboni,muffinresearch/addons-server,mstriemer/olympia,Nolski/olympia,atiqueahmedziad/addons-server,yfdyh000/olympia,mstriemer/addons-server,jamesthechamp/zamboni,spasovski/zamboni,yfdyh000/olympia,diox/olympia,johancz/olympia,Joergen/zamboni,jpetto/olympia,kumar303/addons-server,kumar303/zamboni,Hitechverma/zamboni,psiinon/addons-server,washort/zamboni,harry-7/addons-server,jpetto/olympia,mrrrgn/olympia,jamesthechamp/zamboni,mozilla/addons-server,mdaif/olympia,aviarypl/mozilla-l10n-addons-server,harry-7/addons-server,eviljeff/olympia,muffinresearch/olympia,eviljeff/olympia,anaran/olympia,harikishen/addons-server,mdaif/olympia,mstriemer/olympia,robhudson/zamboni,muffinresearch/olympia,clouserw/zamboni,kumar303/addons-server,bqbn/addons-server,shahbaz17/zamboni,atiqueahmedziad/addons-server,ddurst/zamboni,magopian/olympia,tsl143/zamboni,muffinresearch/addons-server,harikishen/addons-server,Witia1/olympia,Prashant-Surya/addons-server,eviljeff/olympia,Nolski/olympia,psiinon/addons-server,koehlermichael/olympia,jamesthechamp/zamboni,andymckay/olympia,andymckay/zamboni,wagnerand/olympia,beni55/olympia,diox/zamboni,diox/zamboni,psiinon/addons-server,andymckay/zamboni,Jobava/zamboni,kumar303/olympia,kmaglione/olympia,tsl143/zamboni,mstriemer/zamboni,ingenioustechie/zamboni,mrrrgn/olympia,mstriemer/olympia,Joergen/zamboni,wagnerand/zamboni,Prashant-Surya/addons-server,crdoconnor/olympia,diox/olympia,ayushagrawal288/zamboni