Option naming should be more consistent

Motivated by [this SO question](http://stackoverflow.com/questions/41662105/usage-of-buildhaddock-arguments-option-of-stack-yaml) I just [updated](https://github.com/commercialhaskell/stack/commit/72186e79bf4bcf96308838b35be37531974eb13c) the documentation for the `build` options.

Here are a few inconsistencies that I noticed:

* In the yaml config we have `test-arguments`, `haddock-arguments` but `benchmark-opts`.

* We have `test` and `test-X`, `haddock` and `haddock-X`, but `bench` and `benchmark-X`.

* - `--test-arguments` -> `test-arguments: additional-args`
- `--haddock-arguments` -> `haddock-arguments: haddock-args`
- `--benchmark-arguments` -> `benchmark-opts: benchmark-arguments`

* `haddock-deps`, `open-haddocks` and `haddock-internal` should be inside the `haddock-arguments` block

* test `additional-args` and `haddock-arguments` each take a list of strings, while `benchmark-arguments` takes a single string (I didn't check the CLI)