Not require login + added get_comments + added get_user_*

Added kind of a lot over the past month or so.

* Changed **user_name** and **password**  to not required.  This allows the module to run methods without requiring a login.

* Added **get_user_*** collective.  Where * is one of: **overview, comments, submitted, liked, disliked, saved.**  Essentially, returns any information you could want to know about a user. Have fun stalking.

* Added **get_comments** method.  Can't believe I hadn't implemented this earlier! Must have missed it.   I added good documentation on this method - refer to it for usage.  Returns comments of specified post id.

Let me know if you have issues with anything I added. Thanks :)