Remove uinstallable versions of Cairo

Cairo versions > 0.0.0 are not installable on Julia versions < 0.2 due at least to the use of the new `using BinDeps` syntax in place of `require("BinDeps")`.

See: https://groups.google.com/forum/?fromgroups=#!topic/julia-dev/Zi-M7YDE5eo

@StefanKarpinski I wasn't sure if this was the best way to fix this, hence the pull request.