also fixed count behavior according to limit and offset.
fixes #1458

fixes #1560

fixes #1545

fixes #1545

issue #1523

fixes #1469

issue #1313

Moved file and path related methods from StringHelper to FileHelper, renamed StringHelper byte methods not to be misused as string methods

- allows to have dynamic definition of attributes depended on the
  instance
- there was no real need for it to be static. Places that used it static
  have been refactored.

fixes #1318