insert "irrevocably"

source/open-definition-dev.markdown

@@ -36,7 +36,7 @@ A **license** is open if its terms satisfy the following conditions:
 
 ### 3.1. Required Permissions
 
-The **license** *must* grant the following permissions.
+The **license** *must* irrevocably grant the following permissions.
 
 #### 1. Use
 
@@ -219,4 +219,4 @@ places no restrictions monetary or otherwise upon its use.
     * LV: I think not; we're not ever going to be in the business of certifying works, and it will always have to refer to licenses. If it should be moved anywhere, I'd put it in a different document.
 * most of the explanatory comments are gone. maybe the remaining ones should too, and each point be fully self-explanatory
     * LV: That should certainly be a goal.
-* address non-revocability/perpetual license explicitly? see https://twitter.com/owenboswarva/status/409801832869797888
+* address non-revocability/perpetual license [explicitly](https://twitter.com/owenboswarva/status/409801832869797888)? added "irrevocably" before "grant the following permissions".