ctx closer races #270
mux test race #270
fixed dht race #270
fixed race in multiconn
fix(race condition)

https://github.com/jbenet/go-ipfs/issues/270
fix(bitswap_test) race cond

https://github.com/jbenet/go-ipfs/issues/270#issuecomment-61826022
Merge pull request #273 from jbenet/fix-data-races

Fix data races in #270