Make appveyor cache ~/.cargo and target dirs
Make appveyor cache ~/.cargo and target dirs

glandium/sccache,luser/sccache2,luser/sccache2,glandium/sccache,luser/sccache2,mozilla/sccache,mozilla/sccache,glandium/sccache,mozilla/sccache,glandium/sccache,luser/sccache2