Update readme
Update readme

Package zlib1g-dev is required when building native bindings for lxml
on Ubuntu 13.04 (raring)

martinp/jarvis2,martinp/jarvis2,mpolden/jarvis2,Foxboron/Frank,mpolden/jarvis2,mpolden/jarvis2,Foxboron/Frank,Foxboron/Frank,martinp/jarvis2