Implemented CMS storage for user and nodes.

Implemented role and permission storage.
Introduced the CMS_PARTIAL_NODE and CMS_PARTIAL_USER.
Added support for node storage extension
  - storage of data specific to each node content type,
  - in addition to the core CMS_NODE)
  - For now, only implemented for SQL storage.
Note: in current version, CMS_PAGE support is hard coded in the core,
    (as opposed to be only supported by the node module.)
Commented/removed for now, the Web API code to update node summary, title, via REST request.

examples/demo/site/scripts/core.sql

@@ -0,0 +1,33 @@
+BEGIN;
+CREATE TABLE "users"(
+  "uid" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL CHECK("uid">=0),
+  "name" VARCHAR(100) NOT NULL,
+  "password" VARCHAR(100) NOT NULL,
+  "salt" VARCHAR(100) NOT NULL,
+  "email" VARCHAR(250) NOT NULL,
+  "status" INTEGER,
+  "created" DATETIME NOT NULL,
+  "signed" DATETIME,
+  CONSTRAINT "name"
+    UNIQUE("name")
+);
+
+CREATE TABLE "roles"(
+  "rid" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL CHECK("rid">=0),
+  "name" VARCHAR(100) NOT NULL,
+  CONSTRAINT "name"
+    UNIQUE("name")
+);
+
+CREATE TABLE "users_roles"(
+  "uid" INTEGER NOT NULL CHECK("uid">=0),
+  "rid" INTEGER NOT NULL CHECK("rid">=0)
+);
+
+CREATE TABLE "role_permissions"(
+  "rid" INTEGER NOT NULL CHECK("rid">=0),
+  "permission" VARCHAR(255) NOT NULL,
+  "module" VARCHAR(255)
+);
+
+COMMIT;