Remove priority mutex (#644)

* Removed hal::priority_condition_variable

* Replaced uses of priority mutexes with std::mutex and std::recursive_mutex

This allowed replacing a use of std::condition_variable_any with
std::condition_variable.

* Replaced all uses of std::recursive_mutex with std::mutex equivalents

wpilibc/src/main/native/include/PIDController.h

@@ -9,11 +9,10 @@
 
 #include <atomic>
 #include <memory>
+#include <mutex>
 #include <queue>
 #include <string>
 
-#include <HAL/cpp/priority_mutex.h>
-
 #include "Base.h"
 #include "Controller.h"
 #include "LiveWindow/LiveWindow.h"
@@ -148,7 +147,7 @@ class PIDController : public LiveWindowSendable, public PIDInterface {
   std::queue<double> m_buf;
   double m_bufTotal = 0;
 
-  mutable hal::priority_recursive_mutex m_mutex;
+  mutable std::mutex m_mutex;
 
   std::unique_ptr<Notifier> m_controlLoop;
   Timer m_setpointTimer;