Clean up: remove the application module which we don't need for a library.

This is not like the `crypto` subsystem, where a runner is needed to keep the
crypto system up and running. Rather, we can run without an application runner.

src/enacl.app.src

@@ -4,6 +4,5 @@
     {vsn, "0.0.1"},
     {registered, []},
     {applications, [kernel, stdlib]},
-    {mod, {enacl_app, []}},
     {env, []}
 ]}.

src/enacl_app.erl

@@ -1,10 +0,0 @@
--module(enacl_app).
--behaviour(application).
-
--export([start/2, stop/1]).
-
-start(_StartType, _StartArgs) ->
-	enacl_sup:start_link().
-
-stop(_State) ->
-	ok.

src/enacl_nif.erl

@@ -1,5 +1,6 @@
 %%% @doc module enacl_nif provides the low-level interface to the NaCl/Sodium NIFs.
 %%% @end
+%%% @private
 -module(enacl_nif).
 
 %% Public key auth