Features and tweaks

New

• Added menu accelerators for Export, Print and Shortcut Cheatsheet menu items.
• Added support for showing notifications after export completes.
• Added support for Menu or Shift-F10 keyboard shortcut for showing contextual menu.
• Added support for displaying main rows without text as blank rows.
• Added support for joining two rows.
• Added support for hiding header bar and tab bar for focused writing mode.

Changes

• Updated Dutch translation (thanks to Heimen Stoffels)
• Improved look of menu accelerators.
• Changing behavior of row split.
• Updated shortcut cheatsheet.
• Adding top margin to document for improved readability.