Add detailed Tails 1.3 release schedule to the calendar.

Also fix the incorrect date for the February low-hanging fruits
session.

wiki/src/contribute/calendar.mdwn

@@ -2,9 +2,28 @@
 
 * 2015-02-03: [[Monthly meeting|contribute/meetings]]
 
-* 2015-03-12: [[Low-hanging fruits session|contribute/low-hanging_fruit_sessions]]
-
-* 2015-02-24: Release 1.3. anonym is [[contribute/working_together/roles/release_manager]]
+* 2015-02-11:
+  - Feature freeze for Tails 1.3.
+  - Translation window starts for Tails 1.3.
+  - Build and upload Tails 1.3~rc1 ISO image and IUKs.
+  - Start testing Tails 1.3~rc1 during late CET?
+
+* 2015-02-12:
+  - Finish testing Tails 1.3~rc1 by the afternoon, CET.
+  - Release Tails 1.3~rc1 during late CET.
+
+* 2015-02-12: [[Low-hanging fruits session|contribute/low-hanging_fruit_sessions]]
+
+* 2015-02-23:
+  - All translations and bug fixes targeting Tails 1.3 must be merged
+    into the 'testing' branch.
+  - Tor Browser 4.x, based on Firefox 31.5.0esr is *hopefully* out.
+  - Build and upload Tails 1.3 ISO image and IUKs.
+  - Start testing Tails 1.3 during late CET?
+
+* 2015-02-24:
+  - Finish testing Tails 1.3 by the afternoon, CET.
+  - Release Tails 1.3 during late CET.
 
 * 2015-03-03: [[Monthly meeting|contribute/meetings]]