refs#16

In ElemUtils:
- Fix CustomException to avoid random error message due to string object being destroyed in the what() method.

src/ElementaryUtils/logger/CustomException.cpp

 #include "../../../include/ElementaryUtils/logger/CustomException.h"
 
+#include <cstring>
+
 #include "../../../include/ElementaryUtils/string_utils/Formatter.h"
 
 namespace ElemUtils {
@@ -32,7 +34,9 @@ CustomException& CustomException::operator =(
 const char* CustomException::what() const throw () {
     ElemUtils::Formatter formatter;
     formatter << "(" << m_className << "::" << m_funcName << ") " << m_errorMsg;
-    return formatter.str().c_str();
+    char * cstr = new char [formatter.str().length()+1];
+    std::strcpy (cstr, formatter.str().c_str());
+    return cstr;
 }
 
 const std::string& CustomException::getClassName() const {