delete move ctor for ThreadPool (fixes #35)

DESCRIPTION

@@ -1,6 +1,6 @@
 Package: RcppThread
 Title: R-Friendly Threading in C++
-Version: 0.5.3
+Version: 0.5.4.9000
 Authors@R: 
     person("Thomas", "Nagler", email = "mail@tnagler.com", role = c("aut", "cre"))
 Description: Provides a C++11-style thread class and thread pool that can safely
@@ -12,7 +12,7 @@ LazyData: true
 SystemRequirements: C++11
 URL: https://github.com/tnagler/RcppThread
 BugReports: https://github.com/tnagler/RcppThread/issues
-RoxygenNote: 6.1.0
+RoxygenNote: 6.1.1
 Suggests: 
     testthat,
     R.rsp,

inst/include/RcppThread/ThreadPool.hpp

@@ -34,7 +34,7 @@ class ThreadPool {
     ~ThreadPool() noexcept;
 
     ThreadPool& operator=(const ThreadPool&) = delete;
-    ThreadPool& operator=(ThreadPool&& other) = default;
+    ThreadPool& operator=(ThreadPool&& other) = delete;
 
     template<class F, class... Args>
     void push(F&& f, Args&&... args);
@@ -69,7 +69,7 @@ class ThreadPool {
     bool allJobsDone();
     bool waitForWakeUpEvent();
     void rethrowExceptions();
-    
+
     std::vector<std::thread> workers_;        // worker threads in the pool
     std::queue<std::function<void()>> jobs_;  // the task que
 
@@ -382,7 +382,7 @@ inline bool ThreadPool::waitForWakeUpEvent()
 }
 
 //! rethrows exceptions (exceptions from workers are caught and stored; the
-//! wait loop only checks, but does not throw for interruptions) 
+//! wait loop only checks, but does not throw for interruptions)
 inline void ThreadPool::rethrowExceptions()
 {
     checkUserInterrupt();