Ability to pass more options to REPLy

Reason for that is [whidbey](https://github.com/greglook/whidbey/), which needs to pass `:nrepl-context` to REPLy to work correctly. [Here](https://botbot.me/freenode/hoplon/2015-01-29/?msg=30793692&page=3) is the link to IRC chat discussing this problem. It's desirable to have some way of doing that from `.profile.boot`. :)

Start by tracing how .profile.boot configures REPLy and where REPLy options are assembled. Review the linked whidbey context and IRC discussion, then determine how :nrepl-context and other options should be passed; done means whidbey can receive the needed context through .profile.boot.

Written by the indexing model from the issue text.