Prepare release version, gulp build process with code minification

.gitignore

@@ -1,3 +1,4 @@
 .idea/
+node_modules/
 an.wav
 an100ms.wav

LICENCE.md

@@ -0,0 +1,15 @@
+Copyright (c) 2015-2016, Robert Rypuła
+
+Permission to use, copy, modify, and/or distribute this software
+for any purpose with or without fee is hereby granted, provided
+that the above copyright notice and this permission notice appear
+in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
+WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
+THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
+CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
+NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.