Fresh bugfixes straight from the oven

Another Demo Day is here, another stream is approaching - so I had to get this fixed soon

• Fixed "Refresh list" button not adding new entries
• Fixed "Refresh list" button not properly marking deleted entries
• Fixed "Refresh list" button marking new entry covers as "Missing cover"
• Fixed "Download cover" ignoring covers for new entries

New bugs!

• Removed and re-added entries get duplicated instead of removing the "REMOVED" mark. This issue should be purely visual, but it may affect the counters

New features!

• Added "Export" button to the jam overview
• Added text to indicate which style you're using for the jam

Migration instructions

If you are moving from an older version of the app:

• Windows: You need to copy and paste "reviewer_data" directory and the "info.rvctx" file from the old directory to the new one. "info.rvctx" and "reviewer_data" directory should be in the same folder as the "reviewer.exe"
• Mac: Navigate to the old APP in finder, right-click and choose "Show package contents". Navigate to "Contents/Resources" and copy "info.rvctx" file and "reviewer_data" directory somewhere. Navigate to the new APP, "Show package contents", "Contents/Resources" - and paste "info.rvctx" and "reviewer_data" there.
• Linux: Windows instructions should probably work for you.