添加默认笔记本，默认笔记本无法删除。修改初始化数据添加默认笔记本数据。修改bug #23

mongodb_backup/leanote_install_data/themes.metadata.json

@@ -1 +1 @@
-{ "indexes" : [ { "v" : 1, "key" : { "_id" : 1 }, "ns" : "leanote_beta2.themes", "name" : "_id_" } ] }
+{ "indexes" : [ { "v" : 1, "key" : { "_id" : 1 }, "name" : "_id_", "ns" : "leanote.themes" } ] }