Runs DS enabled loop in process (#785)

Solves mutex issues, and other issues with the existing teststand
software. And simplifies the unit test structure.

wpilibcIntegrationTests/src/FRCUserProgram/cpp/TestEnvironment.cpp

@@ -14,11 +14,13 @@
 #include "LiveWindow/LiveWindow.h"
 #include "Timer.h"
 #include "gtest/gtest.h"
+#include "mockds/MockDS.h"
 
 using namespace frc;
 
 class TestEnvironment : public testing::Environment {
   bool m_alreadySetUp = false;
+  MockDS m_mockDS;
 
  public:
   void SetUp() override {
@@ -32,6 +34,8 @@ class TestEnvironment : public testing::Environment {
       std::exit(-1);
     }
 
+    m_mockDS.start();
+
     /* This sets up the network communications library to enable the driver
             station. After starting network coms, it will loop until the driver
             station returns that the robot is enabled, to ensure that tests
@@ -46,7 +50,7 @@ class TestEnvironment : public testing::Environment {
     }
   }
 
-  void TearDown() override {}
+  void TearDown() override { m_mockDS.stop(); }
 };
 
 testing::Environment* const environment =