Implement workspace type check

[jessehouwing]

it looks like agent version 1.x in combination with disabling multiple checkouts results in the behavior that the agent creates a server workspace. All my tasks expect to work against a local workspace.

This behavior is no longer present in agent version 2.0.

Current proposal is to add an explicit error message to the Update Gated Changes and the Check-in task to warn people of this condition.

If someone wants to contribute a TF Checkout task, I'd be happy to include it with the extension, but I'm not going to invest time in this feature for the following reasons:

• Agent 1.x is being phased out in favor of agent 2.x
• Agent 2.x doesn't create server workspaces in this condition.
• Exclusive Checkout has long been e Source Safe migration enabler, but the guidance has always been to move away from this behavior. It's bad enough to do source control operations during build, but doing it with Exclusive Checkout is too much.
• Adding a Check-out task would cause confusion for all those people who do not need it.
• I don't want to add yet another test scenario to the list of scenario's I need to go through when releasing a new version of these tasks.

[jessehouwing]

Related to: #36 and #37

[jessehouwing]