Fix for testing #38 - VS cannot run [Theory] tests with multiple

parameters

The problem here is the way we're using for VS to communicate with the
test runner via the commandline isn't very well suited for the problem
space.

If VS wants to run `MyTestClass.Test1` and `MyTestClass.Test2` then it will
build a commandline like:

`k test --design-time --test MyTestClass.Test1,MyTestClass.Test2`

The runner knows to split the argument on `,` or `;` and then we have the test
names to run. This is problematic when the test name contains either of
these characters.

VS is taking a change to pass the test 'fully-qualified-name' instead of display name. That will look like:
`k test --design-time --test <guid1>,<guid2>`

We'll do a full solution in the next phase of the test adapter.
@davidfowl 

Quick fix for this is that we're actually passing the uniqueId to VS (it's a guid :heart:). VS is taking a change to pass the uniqueId back to us and we'll use that to select the tests. 

Since the uniqueId is just a guid there's no parsing needed.