update license to CC-BY-SA-4.0, see todbot/blink1#337

LICENSE.txt

@@ -1,35 +1,13 @@
-
-Copyright (c) ThingM, 2012-2018
+blink1-tool and blink(1) Copyright (c) by ThingM, 2012-2020
 
 'blink(1)' is a trademark of ThingM Corporation
 
----
-
-LICENSE:  
-Creative Commons - Attribution - ShareAlike 3.0 
-http://creativecommons.org/licenses/by-sa/3.0/
-See why we chose this license: http://www.inmojo.com/licenses/
-
-This work is licensed under the Creative Commons Attribution-ShareAlike 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by-sa/3.0/ or send a letter to Creative Commons, 444 Castro Street, Suite 900, Mountain View, California, 94041, USA.
-
-
-This is a human-readable summary of the full license.
-
-You are free:
-- to Share - to copy, distribute and transmit the work, and
-- to Remix - to adapt the work
+========================
 
-Under the following conditions:
-- Attribution - You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work.)
-- Share Alike - If you alter, transform, or build upon this work, you may distribute the resulting work only under the same, similar or a compatible license.
+blink1-tool is licensed under a
+Creative Commons Attribution-ShareAlike 4.0 International License.
 
-With the understanding that:
-- Waiver - Any of the above conditions can be waived if you get permission from the copyright holder.
-- Other Rights - In no way are any of the following rights affected by the license:
--- your fair dealing or fair use rights;
--- the author's moral rights; and
--- rights other persons may have either in the work itself or in how the work is used, such as publicity or privacy rights.
+You should have received a copy of the license along with this
+work. If not, see <http://creativecommons.org/licenses/by-sa/4.0/>.
 
-Notice - For any reuse or distribution, you must make clear to others the license terms of this work. The best way to do that is with a link to 
-http://creativecommons.org/licenses/by-sa/3.0/