Start adding composer support

* Add app and framework composer files.
* Remove globals plugins & vendors directories, they will be unused
  once composer support is complete so remove them now.
* Remove the top level composer file.  It won't be used either.

App/composer.json

@@ -0,0 +1,15 @@
+{
+    "name": "cakephp/app",
+    "description": "CakePHP skeleton app",
+    "homepage": "http://cakephp.org",
+    "license": "MIT",
+    "require": {
+        "cakephp/framework": "dev-3.0",
+        "php": ">=5.4"
+    },
+    "autoload": {
+        "psr-0": {
+            "App\\": "."
+        }
+    }
+}

composer.json → lib/composer.json

@@ -1,5 +1,5 @@
 {
-    "name": "cakephp/cakephp",
+    "name": "cakephp/framework",
     "description": "The CakePHP framework",
     "type": "library",
     "keywords": ["framework"],
@@ -22,10 +22,10 @@
     },
     "autoload": {
         "psr-0": {
-            "Cake": "lib/Cake/"
+            "Cake\\": "Cake/"
         }
     },
     "bin": [
-        "lib/Cake/Console/cake"
+        "Cake/Console/cake"
     ]
 }