WordPress plugin readme: add v1.1 upgrade notice, polish changelog

readme.txt

@@ -78,17 +78,24 @@ A. Sure, go ahead! It is completely open source.
 == Changelog ==
 
 = 1.1 =
-Removed `Attachment` field type, with backward compatibility.
-The `File` and `Image` field types now save the attachment ID by default.
-Introduced `File_Field::set_value_type()` to easily change the saved value type.
-Added a Vagrantfile.
-Added some `Field` and `Container` tests.
-Renamed `Date_Field::set_options()` to `Date_Field::set_datepicker_options()`.
-Introduced an abstract `Predefined_Options_Field` base for `Select`, `Radio` and `Set` field types.
-Added proxy Container, Field and Widget for shorter `use` statements.
-Introduced an abstract `Scripts_Field` base for `Header Scripts` and `Footer Scripts` field types.
-Introduced an abstract `Meta_Datastore` base for all meta datastore classes.
-Performed various other code fixes and improvements.
+* Removed `Attachment` field type, with backwards compatibility.
+* The `File` and `Image` field types now save the attachment ID by default.
+* Introduced `File_Field::set_value_type()` to easily change the saved value type.
+* Added a Vagrantfile.
+* Added some `Field` and `Container` tests.
+* Renamed `Date_Field::set_options()` to `Date_Field::set_datepicker_options()`.
+* Introduced an abstract `Predefined_Options_Field` base for `Select`, `Radio` and `Set` field types.
+* Added proxy Container, Field and Widget for shorter `use` statements.
+* Introduced an abstract `Scripts_Field` base for `Header Scripts` and `Footer Scripts` field types.
+* Introduced an abstract `Meta_Datastore` base for all meta datastore classes.
+* Performed various other code fixes and improvements.
 
 = 1.0 =
-Initial version.
+* Initial version.
+
+== Upgrade Notice ==
+
+= 1.1 =
+The `File` and `Image` field types now save the attachment ID by default.
+The `Attachment` field type has been removed and now falls back to `File`.
+The `Date_Field::set_options()` method is now `Date_Field::set_datepicker_options()`.