Implement probe_lua and add it to lpxclient/lpxserver

luprex/core/cpp/util.hpp

@@ -77,6 +77,10 @@ int common_prefix_length(const std::string &a, const std::string &b);
 std::string tolower(std::string input);
 std::string toupper(std::string input);
 
+// Return true if the string has the specified prefix or suffix.
+bool has_prefix(const std::string &s, const std::string &prefix);
+bool has_suffix(const std::string &s, const std::string &suffix);
+
 // Return true if the string can be parsed as an integer.
 bool validinteger(const std::string &value);