added object_cache and test

source/core/CMakeLists.txt

@@ -123,6 +123,7 @@ add_library(matador-core STATIC
   ../../include/matador/object/collection_utils.hpp
   object/collection_utils.cpp
   ../../include/matador/object/pk_field_locator.hpp
+  ../../include/matador/object/object_cache.hpp
 )
 
 target_link_libraries(matador-core ${CMAKE_DL_LIBS})

source/core/utils/identifier_to_value_converter.cpp

@@ -39,10 +39,6 @@ void identifier_to_value_converter::serialize(uint64_t &x, const field_attribute
   value_ = x;
 }
 
-void identifier_to_value_converter::serialize(const char *x, const field_attributes &) {
-  value_ = x;
-}
-
 void identifier_to_value_converter::serialize(std::string &x, const field_attributes &) {
   value_ = x;
 }