Some small improvements and fixes

- date helper: method getMysqlDatetime() now correctly converts the date if the default input format is used
- Tagmanager: now modulenames with underscore are possible ("ron_mymodule") - helps avoiding interference
- base model: _process_where() now also accepts "RAW" as key for more advanced where-phrases
- small cleanup: removing tabs on empty lines, spaces at end of lines (less whitespace = less ram used for parsing)