Add follow_links method to spider. Add base_url attribute to spider.
Add follow_links method to spider. Add base_url attribute to spider.

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