Update user_agent.txt (now only recent versions of FF and chrome)
Update user_agent.txt (now only recent versions of FF and chrome)

codevlabs/grab,istinspring/grab,raybuhr/grab,codevlabs/grab,alihalabyah/grab,shaunstanislaus/grab,subeax/grab,shaunstanislaus/grab,SpaceAppsXploration/grab,DDShadoww/grab,liorvh/grab,huiyi1990/grab,maurobaraldi/grab,istinspring/grab,liorvh/grab,subeax/grab,giserh/grab,giserh/grab,huiyi1990/grab,subeax/grab,raybuhr/grab,pombredanne/grab-1,DDShadoww/grab,lorien/grab,SpaceAppsXploration/grab,pombredanne/grab-1,lorien/grab,maurobaraldi/grab,kevinlondon/grab,alihalabyah/grab,kevinlondon/grab