Require zendframework/zendframework1 ~1.12 in development

Test ZendHttp adapter in CI environment

composer.json

@@ -17,7 +17,8 @@
     },
     "require-dev": {
         "phpunit/phpunit": "~3.7",
-        "squizlabs/php_codesniffer": "~1.4"
+        "squizlabs/php_codesniffer": "~1.4",
+        "zendframework/zendframework1": "~1.12"
     },
     "extra": {
         "branch-alias": {