Remove file TODOPORT

Summary:
This is the latest status of the items on the now deleted list:

• 2007: SOMETIMES BUTTONS IN MAIN DIALOG MAKE KSUDOKU CRASH
  • 2018: Is this still an issue?
• 2007: export system
  • 2018: What is meant by that?
• 2007: status bar text disappear sometimes
  • 2018: Is this still an issue?
• 2007: flickering
  • 2018: Is this still an issue?
• 2007: knewstuff crashes
  • 2018: Where is this used?
• 2007: KConfig
  • 2018: Is this still an issue?

Reviewers: KDE Games

Subscribers: aacid, kde-games-devel

Differential Revision: https://phabricator.kde.org/D12900