A directory-category for terminal emulators

This is a mostly cosmetical commit, in the sense it doesn't change the contents
of any package, but reorganizes the overall Nixpkgs expressions.

Terminal emulators are an ubiquitous tool for any Unix user; even the beginners
are routinely familiarized to it. And, manifestly, there are many
implementations of terminal emulators out there, from those traditionally made
in C and C++ to those written in Haskell and Go.

Terminal emulators deserve more highlight. This commit does that by creating a
category for them.

pkgs/applications/terminal-emulators/yaft/default.nix

@@ -0,0 +1,25 @@
+{ stdenv, fetchFromGitHub, ncurses }:
+
+stdenv.mkDerivation rec {
+  version = "0.2.9";
+  pname = "yaft";
+
+  src = fetchFromGitHub {
+    owner = "uobikiemukot";
+    repo = "yaft";
+    rev = "v${version}";
+    sha256 = "0l1ig8wm545kpn4l7186rymny83jkahnjim290wsl7hsszfq1ckd";
+  };
+
+  buildInputs = [ ncurses ];
+
+  installFlags = [ "PREFIX=$(out)" "MANPREFIX=$(out)/share/man" ];
+
+  meta = {
+    homepage = "https://github.com/uobikiemukot/yaft";
+    description = "Yet another framebuffer terminal";
+    license = stdenv.lib.licenses.mit;
+    maintainers = [ stdenv.lib.maintainers.matthiasbeyer ];
+    platforms = with stdenv.lib.platforms; linux;
+  };
+}