do not require wget to be installed for this module to work.

As OSX has only curl by default.

bumped version
Why `test` the result of the execution of `which`? This could be written `if which wget`, since the exit status of `which` is non-0 if the executable is not found.

Also, I'd make this silent with ` > /dev/null` to avoid having the path to the executable be printed on each execution (unfortunately, the `-s` option is not portable; if we only support OSX then we can use `-s` instead).