Updated forEach object example to include the keys. [ci skip]  [closes #596]

The forEach object example is a little ambiguous where it says "logs each number", since both the key and value of the object are technically numbers. I've read it a few times now (skipping over the function description of course) and wanted it to be a little more obvious.
Cleanup `_.forEach` docs. [ci skip]
Fix `_.template` and `_.flatten` use in perf/perf.js.
Split `_.every`, `_.filter`, `_.map`, `_.reduce`, & `_.some` into `arrayXYZ` and `baseXYZ` forms as well as specialize for `_.bind` and `_.partial`.
Rebuild dist.