Merge pull request #585 from BlueRaja/DontFetchInventoriesSynchronously

Don't fetch Inventory synchronously
Merge pull request #582 from scholtzm/UserHandlerDisposal

Added code for UserHandler disposal.
Add BlueRaja to Contributors.

>Jessecar96 added BlueRaja to Jessecar96/SteamBot  8 hours ago
Update BlueRaja's link
Merge pull request #596 from SephirothSG/patch-1

Add BlueRaja to contributors.
Small refactoring in preparation for fixing the 'ItemRemoved event not fired' vulnerability
Changed type of 'MyOfferedItems' and 'OtherOfferedItems' from List<ulong> to IEnumerable<TradeUserAssets>.

This is necessary for the upcoming security patch.
Make TradeUserAssets immutable, equatable, comparable.
Fix for https://github.com/Jessecar96/SteamBot/issues/602 - exploit caused by Steam sometimes not correctly sending the ItemAdded/ItemRemoved events
Merge branch 'FixItemRemovedEvent'

Conflicts:
	SteamTrade/Trade.cs