Fix multiple unnamed enum seq/map variants
Fix multiple unnamed enum seq/map variants

Closes #32.

oli-obk/rust-serde,Hoverbear/serde,tempbottle/serde,sidred10/serde,JohnHeitmann/serde,infinityb/serde,pcwalton/serde,serde-rs/serde,3Hren/serde,eefriedman/serde,skade/serde,csmulhern/serde,Ticki/serde,jmesmon/serde,thorbenk/serde,erickt/serde,Byron/serde