Add merge-with
Merge pull request #106 from tgriesser/merge-with

Add merge-with
Adds join, index, project, map-invert, rename, rename-keys
Merge pull request #107 from tgriesser/set-ops

Adds join, index, project, map-invert, rename, rename-keys
bump deps add reducers benchmark
Merge branch 'master' of github.com:swannodette/mori
tweak
fix reducers example
clarify Map/Set interface
bump year