refactor(client): use public interface exclusively

This commit demotes the komorebi-core crate to a module (core) inside of
the komorebi lib, resulting in the komorebi-client crate lib becoming
the single public interface for programming in Rust against komorebi.

komorebic and komorebi-gui now consume komorebi-client exclusively as
the means for sending and receiving messages to and from komorebi, so
that anyone wishing to integrate with komorebi will have all of the same
functionality to them as I do.

README.md

@@ -279,7 +279,7 @@ If the named pipe exists, `komorebi` will start pushing JSON data of successfull
 
 You may then filter on the `type` key to listen to the events that you are interested in. For a full list of possible
 notification types, refer to the enum variants of `WindowManagerEvent` in `komorebi` and `SocketMessage`
-in `komorebi-core`.
+in `komorebi::core`.
 
 Below is an example of how you can subscribe to and filter on events using a named pipe in `nodejs`.
 
@@ -414,7 +414,7 @@ A TCP listener can optionally be exposed on a port of your choosing with the `--
 provided to `komorebi` or `komorebic start`, no TCP listener will be created.
 
 Once created, your client may send
-any [SocketMessage](https://github.com/LGUG2Z/komorebi/blob/master/komorebi-core/src/lib.rs#L37) to `komorebi` in the
+any [SocketMessage](https://github.com/LGUG2Z/komorebi/blob/master/komorebi/src/core/mod.rs#L37) to `komorebi` in the
 same way that `komorebic` would.
 
 This can be used if you would like to create your own alternative to `komorebic` which incorporates scripting and