Added separate permissions for editing and deleting karma (both as a user and as a mod), and implemented deletion of karma in the edit screen. Now I only need to allow mods without m_karma_edit but with m_karma_delete to delete reported karma using a separate button :).
Fixed a nasty fly-under-the-radar-bug that caused wrong item data to be shown with karma reports.
Moderators with m_karma_delete but without m_karma_edit may now delete reported karma. However, confirm_box() is currently malfunctioning on controller URLs until http://tracker.phpbb.com/browse/PHPBB3-11850 is fixed. Manually fixing the action URL with an element inspector does the trick :P.
Cancelling the delete karma confirm_box is now handled, though the handling could still be improved.
Enabled closing/deleting karma reports in overview mode and fixed a bug where no success message was displayed when closing/deleting multiple karma reports.
Use INCLUDECSS for proper CSS file inclusion so it now works on controller pages :).
Fix some missing final newlines.
Switched all ugly link generation with hardcoded app.php references to phpbb_controller_helper::url() method calls, plus fixed a wrongly indented function I happened to spot.
Got rid of some TODOs in mcp/reported_karma.php.
The report karma link isn't shown anymore for karma that is already reported.
It is no longer possible to report karma given to others than yourself.
There now is a return link and meta-refresh from the "karma successfully reported" page.
Fixed variable declarations in the reportkarma controller.
Improved some translation names.
Karma permissions now have their own category :).
The old tests should work and pass again now; I should probably write some more.
Changed copyright to phpBB instead of rechosen.
Made composer.json MichaelC-compliant.
Sadly, MichaelC-compliant doesn't work with develop :P.
Woops, forgot to change services.yml when I updated the constructor arguments of the reportkarma controller :P.