mono-traversable-0.7.0: ChangeLog.md

## 0.7.0

* Work on better polymorphic containers
    * Rename `mapKeysWith` to `omapKeysWith`
    * Add new class `BiPolyMap`
    * Add `keys` to `IsSet`
    * New class `HasKeysSet`
* Added `index`, `indexEx` and `unsafeIndex`.
* Added `sortOn`