Handle the common csv double quote escape variation (repeating the double quote)

gnucash/import-export/csv-imp/gnc-tokenizer-csv.cpp

@@ -76,6 +76,16 @@ int GncCsvTokenizer::tokenize()
                 bs_pos = line.find ('\\', bs_pos);
             }
 
+            // Deal with repeated " ("") in strings.
+            // This is commonly used as escape mechanism for double quotes in csv files.
+            // However boost just eats them.
+            bs_pos = line.find ("\"\"");
+            while (bs_pos != std::string::npos)
+            {
+                line.replace (bs_pos, 2, "\\\"");
+                bs_pos = line.find ("\"\"");
+            }
+
             Tokenizer tok(line, sep);
             vec.assign(tok.begin(),tok.end());
             m_tokenized_contents.push_back(vec);

gnucash/import-export/csv-imp/test/test-tokenizer.cpp

@@ -176,6 +176,7 @@ static tokenize_csv_test_data comma_separated [] = {
         { "05/01/15,45,Acme Inc.,,Miscellaneous,", 6, { "05/01/15","45","Acme Inc.","","Miscellaneous","",NULL,NULL } },
         { "Test\\ with backslash,nextfield", 2, { "Test\\ with backslash","nextfield",NULL,NULL,NULL,NULL,NULL,NULL } },
         { "Test with \\\" escaped quote,nextfield", 2, { "Test with \" escaped quote","nextfield",NULL,NULL,NULL,NULL,NULL,NULL } },
+        { "Test with \"\" escaped quote,nextfield", 2, { "Test with \" escaped quote","nextfield",NULL,NULL,NULL,NULL,NULL,NULL } },
         { NULL, 0, { NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL } },
 };