v0.5.0

Fix haskey for PersistentHashMap (#50)

Julia 0.7 and 1.0 support

Merge pull request #43 from rdeits/rd/iterate

update to new Base.iterate protocol

0.6 compat

Merge pull request #35 from TotalVerb/fw/v0.6

Update for v0.6

bug fix

make size return a tuple cc @mbauman

Refresh

deprecation fixes, use of Pair.