Core/Misc: EventMap will no longer inherit from std::map
Core/Misc: Replaced some macro definitions with inline functions
Core/Misc: Use equal_range instead of lower_bound/upper_bound calls where possible.
Core/Misc: Some minor changes here and there
Core/Mysql: Multiple changes
- added support for setting NULL column values to MySQL wrapper in core
- replaced nonstandard strdup function and manual memory management with std::string
- fixed bug in MySQLPreparedStatement::getQueryString method, it failed when string parameter contained embedded '?' symbols
- fixed memory leak in MySQLPreparedStatement::setString method