Update for first release

Author: korthaj

README.md

@@ -20,8 +20,11 @@ There is an online reference for the package at
 
 ### Roadmap
 
-* The API of this library is not yet frozen.
-* Version numbers will adhere to [semantic versioning][sv].
+* The API of this library is frozen.
+* Version numbers adhere to [semantic versioning][sv].
+
+The only accepted reason to modify the API of this package is to handle
+bug fixes that can't be resolved in any other reasonable way.
 
 ### Thanks