C++: Moved all C++ examples to own folder

* moved C++ examples to a new cxx folder in
  examples
* added experimental C++ component
* added ESPException class to the C++ experimental
  component
* added test cases for ESPException and
  corresponding test macros

examples/cxx/experimental/experimental_cpp_component/test/unity_cxx.hpp

@@ -0,0 +1,35 @@
+#ifndef UNITY_CXX_H_
+#define UNITY_CXX_H_
+
+#include "unity.h"
+
+#define STR(x) #x
+
+/**
+ * Very simple helper macro to catch exceptions.
+ *
+ * @note
+ *  * If there is any exception which not a child of std::exception, it will terminate the program!
+ *  * If there is no exception, it will jump from the current frame without de-initializing
+ *    destructors!
+ */
+#define TEST_THROW(expr_, exception_) \
+    do { \
+        bool caught = false; \
+        bool caught_different = false; \
+        try { \
+            expr_; \
+        } catch ( exception_ &e) { \
+            caught = true; \
+        } catch ( std::exception &e) { \
+            caught_different = true; \
+        } \
+        TEST_ASSERT_FALSE_MESSAGE(caught_different, "ERROR: Expected " STR(exception_) \
+                ", but caught different exception."); \
+        TEST_ASSERT_TRUE_MESSAGE(caught, "ERROR: Expected " STR(exception_) \
+                ", but no exception thrown."); \
+    } \
+    while (0)
+
+
+#endif // UNITY_CXX_H_