FlashFXP 5.2.0 build 3903

- Fixed incorrect file list column order on restart (if the columns were re-ordered).
- Fixed issue with file list columns not retaining their defined size when "auto size file list columns" was unchecked.
- Fixed rare crash when the system theme is changed (triggered by invalid WinProc reference while re-creating the window handle).
- Fixed rare crash on exit caused by an invalid memory overwrite.
- Fixed non-fatal issue where some code was not executed for scheduled tasks (resulted in incorrect UI if the main window is shown while task is running).
- Fixed incorrect drawing of the checklist box control, the wrong part was used for the intermediate state (was using the intermediate disabled part).