Use `wget` in travis setup
Use `wget` in travis setup

Switch to using `wget` instead of `curl` in travis setup so that site
redirection will work when downloading source packages to install.

xyliuke/busted,sobrinho/busted,istr/busted,DorianGray/busted,o-lim/busted,leafo/busted,ryanplusplus/busted,Olivine-Labs/busted,mpeterv/busted,nehz/busted