Refactored settings and added collection settings

Refactored settings to be a little more conceptually understandable and
added settings for collection retrieval.
added comments to bgsettings.cs
Refactored settings classes & added collection

The settings classes have been refactored further to help project
structure.  A collection class has also been added.
Added function for getcollection to client

Client can now retrieve collections from BGG.
Added function to use settings for getCollection

client object now has additional getCollection arguments to accept the
Collection Settings objects and apply them by altering the url string.