Document linking Haskell wrapper when building from source

Currently the installation instructions for `arrayfire-haskell` target users who install binaries into `/lib` / `lib64` on `OSX`/ `Linux` respectively. For "power users" (those who build from source), there should be instructions on how to install.

```bash
cabal configure -f-disable-default-paths --extra-lib-dirs=/path/to/arrayfire/lib --extra-include-dirs=/path/to/arrayfire/include
```