Fix `_.forEachRight`, `_.forInRight`, and `_.findLastIndex` and add related unit tests.
Simplify `iteratorObject` use for `underscore` builds and make `_.mixin` and `_.template` work better for `modularize underscore` builds.
Add build tests for findIndex, findKey, findLast, findLastIndex, findLastKey. forEachRight, forInRight, and forOwnRight.
Add find unit tests.
Simplify package.json description.