Change license to CC-BY-4.0 (#2)

 * Since original intention was using MIT-License style, I believe
   using CC-BY-4.0 would be better fit to this project.
 * Instead of put the original CC license words in `LICENSE` file,
   referencing it with a copyright sentence, which can annotate
   the project in a simple way.

LICENSE

@@ -1,20 +1,7 @@
-Copyright (c) 2018 Yoshimasa Niwa
+ramen (c) by Yoshimasa Niwa
 
-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:
+ramen is licensed under a
+Creative Commons Attribution 4.0 International License.
 
-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.
+You should have received a copy of the license along with this
+work. If not, see <http://creativecommons.org/licenses/by/4.0/>.