Refactored enter mode:

1. editor#enterMode (and related) are now named editor#activeEnterMode.
2. editor#enterMode and #shiftEnterMode keep default modes.
3. htmlDP#toHtml and #toDF accept enterMode as an option and it defaults to editor#activeEnterMode.
4. when processing nested editable its enter mode is used if it has defined filter or editor's main enter mode is used.
Pass enter mode to used filter.