Merge pull request #20 from Randy-Ma/master

Fix issues when running by category
New installer.
Use test assembly name as the results root.
Cleanup
Add the ShouldRun parameter.
Refactor tests and add test for exclude.
Comment one debug statement.
SetupTests does not require a parameter.
Add selected test summary.
Switching grouping type refreshes.
Don't hold reference to sorting group.
Add 2 tests.
Cleanup
Move conditional run logic to Refresh.
Add one more test.
New installer.
Move arg parsing to Runner for testability.
New installer.
Make it possible to support multiple categories