1. implement tracing stack when got exception

2. binding function name
3. implement sandbox for isolate throw exception
4. implement object expression
5. implement get, set object operation
6. implement logical and, or operation

Signed-off-by: seonghyun kim <sh8281.kim@samsung.com>

src/runtime/StringObject.cpp

@@ -0,0 +1,14 @@
+#include "Escargot.h"
+#include "StringObject.h"
+#include "Context.h"
+
+namespace Escargot {
+
+StringObject::StringObject(ExecutionState& state, String* value)
+    : Object(state)
+    , m_primitiveValue(value)
+{
+    setPrototype(state, state.context()->globalObject()->stringPrototype());
+}
+
+}