Add secure getter to ScriptableRequest.

secure is true if the client is using SSL.
Convert between BSONValue and JavaScript value with field information.

Currently, ScriptableCollection doesn't consider field type when saving data.
It causes a type error on reading data even when the data is convertable to the
required type.
Support Date type on DB API.

Currently, there is a bug in saving Date type. This patch fixes the bug and
adds an example of saving Date.
Convert to the requested type when reading a document from database.

Currently, ScirptableDocument reads data only if the saved data type is exactly
the same to the specified type in schema. This patch makes ScriptableDocument
convert the data to a compatible type if possible.
Implement remove and removeOne method of ScriptableCollection.

And add examples.
Implement Authenticated.

There is no reason to use actor for UserAction because most of the
hard works handled by UserAction are moved to GamePluginWorker
and UserAction is just used to filter logged-in requests.

UserActionActor will be removed in the next patch.
Replace UserAction with Authenticated.