NeovimT transformer

[saep]

I'm currently exploring the possibility of defining the Neovim context as a monad transformer. Apart from being slightly more complicated to initialize, this approach seems to be way more flexible than the current one. I found it quite hard to start a ghc-mod context with the current model and therefore I am exploring this design space before commiting to a (somewhat) final API design for version 0.1.

[saep]

It turns out to be a lot of work and with the rise of the haskell-ide-engine, it might not be worth the effort. If somebody wants to take a stab at this, I would implement it roughly in these steps:

• Figure out a way to register (currently) stateful commands from some custom monad transformer stack. This is very important and probably the most difficult thing to do.
• Remove the StateT transformer and make everything compile
• Add a type class that has a method which knows how to get the necessary data value to communicate with neovim (i.e. Neovim.Context.Internal.Config
• Possibly transform the ReaderT wrapper in something specific to nvim-hs, so that we don't steal that instance.
• Make it convenient to use. Preferably even more convenient than the current stateful plugin component. :-)

[saep]

A simple HasNvim typeclass is probably better.