litle fix in utils trim

+ added 2 functions to check script output
+ created a html page with 4 forms for tests
+ created 2 cpp forms, with and without creating header content-length

srcs/utils.cpp

@@ -226,7 +226,7 @@ std::string
 	begin = str.rfind(delim, pos);
 	if (begin == NPOS)
 		begin = 0;
-	else
+	else if (begin < pos)
 		begin += delim.size();
 
 	end = str.find(delim, pos);