kiss: add license header

It can now be distributed as a single file while keeping license
intact.

kiss

@@ -1,10 +1,29 @@
 #!/bin/sh
 # shellcheck source=/dev/null
 #
-# This is a simple package manager written in POSIX shell for use
-# in KISS Linux (https://kisslinux.xyz).
+# Simple package manager written in POSIX shell for https://kisslinux.xyz
 #
-# Created by Dylan Araps.
+# The MIT License (MIT)
+#
+# Copyright (c) 2019-2021 Dylan Araps
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
 
 log() {
     printf '%b%s %b%s%b %s\n' \