Fix leveldb change skew

Make leveldb match the changes in syndtr/leveldb API due to breakages at
syndtr/goleveldb@63c9e64.
Merge pull request #188 from kortschak/leveldb

Fix leveldb change skew
temporary travis fix
Merge pull request #189 from barakmich/testdeps

temporary travis fix
Merge branch 'master' into gaedatastore