3.0.0 preparations

- Added CHANGELOG date
- Updated branch aliases:
  - dev-master => 3.0-dev
  - dev-develop => 3.1-dev

Author: weierophinney

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 All notable changes to this project will be documented in this file, in reverse chronological order by release.
 
-## 3.0.0 - TBD
+## 3.0.0 - 2016-04-28
 
 This version contains a number of changes to required dependencies, error
 handling, and internals; please read [the migration document](doc/book/migration.md)

composer.json

@@ -25,8 +25,8 @@
     "prefer-stable": true,
     "extra": {
         "branch-alias": {
-            "dev-master": "2.7-dev",
-            "dev-develop": "3.0-dev"
+            "dev-master": "3.0-dev",
+            "dev-develop": "3.1-dev"
         }
     },
     "autoload-dev": {