Add Sleep and Lock utilities

src/Thread.h

 #ifndef ADBLOCKPLUS_THREAD_H
 #define ADBLOCKPLUS_THREAD_H
 
 #ifdef WIN32
 #include <windows.h>
 #else
 #include <pthread.h>
 #endif
 
 namespace AdblockPlus
 {
+  void Sleep(const int millis);
+
   class Mutex
   {
   public:
 #ifdef WIN32
     CRITICAL_SECTION nativeMutex;
 #else
     pthread_mutex_t nativeMutex;
 #endif
 
     Mutex();
     ~Mutex();
     void Lock();
     void Unlock();
   };
 
+  class Lock
+  {
+  public:
+    Lock(Mutex& mutex);
+    ~Lock();
+
+  private:
+    Mutex& mutex;
+  };
+
   class ConditionVariable
   {
   public:
     ConditionVariable();
     ~ConditionVariable();
     void Wait(Mutex& mutex);
     void Signal();
 
   private:
 #ifdef WIN32
@@ skipping 14 matching lines @@
   private:
 #ifdef WIN32
     HANDLE nativeThread;
 #else
     pthread_t nativeThread;
 #endif
   };
 }
 
 #endif