Adds "exec" command and other BotManager tweaks.

Allows commands to be given directly to bots via the BotManager
console.This command is handled in the UserHandler's `OnBotCommand`.

Other changes include threading the BotManager commands and
slightlychanging the way accounts are authorized while
`UseSeparateProcesses  = true`.

Extended functionality of the "start", "stop", and "auth" commands to
allow usernames as well as indexes.

Also fixed the `Console.Title` being set to the last bot to be
configured while in Separate Processes mode.
Removes command threading. Username comparisons changed to ignore case.

As per suggestions, the bot command is no longer threaded, and a couple
conditionals are inverted. This also modifies username comparisons which
now use `StringComparison.CurrentCultureIgnoreCase`.
Merge pull request #434 from gabrielmtzcarrillo/SteamInventory

Steamtrade addon
Merge pull request #426 from thesandvichisaliar/ExecCmd-Addition

Adds "exec" command and other BotManager tweaks.
small fix

Fixed: stop loading entire type list when reach a success: false
Added: Add/Remove non TF2 items

It's not fully merged with Trade.cs
small fixes
small fixes
Small Trade & TradeSession Clean up
Small fixes +  Tiny clean up

Removed appId description from TradeSession, Changed  types to
ContextIds from Load() in GenericInventory + small fix &  Added part of
TheAnthonyNL's suggested code.