Add @license JSDoc tag.

build/mathquill.js

diff --git a/build/mathquill.js b/build/mathquill.js
index 3d06a92..b4614b1 100644
--- a/build/mathquill.js
+++ b/build/mathquill.js
@@ -1,4 +1,5 @@
 /**
+ * @license
  * MathQuill v0.10.1, by Han, Jeanine, and Mary
  * http://mathquill.com | maintainers@mathquill.com
  *

build/mathquill.min.js

diff --git a/build/mathquill.min.js b/build/mathquill.min.js
index 483d258..2f6ed9f 100644
--- a/build/mathquill.min.js
+++ b/build/mathquill.min.js
@@ -1,4 +1,5 @@
 /**
+ * @license
  * MathQuill v0.10.1, by Han, Jeanine, and Mary
  * http://mathquill.com | maintainers@mathquill.com
  *