Added the branch alias for master and fixed requirements

Author: stof

composer.json

@@ -10,7 +10,12 @@
  ],
  "require": {
  "php": ">=5.3.2",
- "ezyang/htmlpurifier": "~4"
+ "ezyang/htmlpurifier": "~4.0"
+ },
+ "extra": {
+ "branch-alias": {
+ "dev-master": "1.0.x-dev"
+ }
  },
  "autoload": {
  "psr-0": { "Exercise\\HTMLPurifierBundle": "" }