See description

- New method for getting file size
- Don't use index for selecting tab
- Add new 'Convert' tab for converting & cutting
- Removed 'ConvertDialog' form and 'Convert' & 'Cut Audio' menu items
Suggest file name if output is empty
Fix CheckBoxes
Make 'DeleteFile' static
Handle situations where input & output matches

FFmpeg doesn't seem to be able to overwrite input
Remove delay from 'DeleteFile'
Remove debugging
Match input & output when converting download