Admin features

Added following functions to the pb.AdminNavigation

    pb.AdminNavigation.add(node)
    pb.AdminNavigation.addChild(parentId, node)

addChild can be called at any time even before the parent tree node exists, this is just in case someone will ever need to do something like this. The navigation will only be built once on startup so the overhead should be really low.

i also added an adminSample Plugin to show off the admin related features.
I quickly ran this test:

    var testObj = {
        test: {
            test: {
                test: "test",
                test2: [
                    1,2,3,4,5,6,7,8
                ]
            }
        }
    };

    console.time("deepMerge");
    for(var i = 0; i < 10000; i++) {
        pb.utils.deepMerge(testObj, {});
    }
    console.timeEnd("deepMerge");
    console.time("clone");
    for(var i = 0; i < 10000; i++) {
        pb.utils.clone(testObj);
    }
    console.timeEnd("clone");


deepMerge: 102ms
clone: 34ms

im really impressed how fast JSON.parse/stringify is :D