Canvas-grab

- Some files on Canvas have unknown size and cannot be downloaded. Now they will be skipped instead of crashing the program.
- Better support for image files. Now when downloading these files, their size will be shown in progress bar.
- New whitelist mode. Only download selected courses.
- [dev] `.checkpoint` file is more readable.
- [dev] Internal structure has been refactored.

Good luck in final exam!

If you have any question, have any advice, or want new features, feel free to create an issue at https://github.com/skyzh/canvas_grab/issues

This is a hotfix to ignore file with unknown size. If you encountered this issue, please download this hotfix version v1.7.7. Otherwise, use stable version below.

- Even faster module resolving by using file cache. This is only supported in courses with module and file functionality both enabled.
- Download failure can be handled gracefully. Now the program won't exit if a file fails to download.
- Better support for courses with nickname. You can use `NICKNAME` in course folder config.
- You can now disable version check in config.

- canvas_grab now concurrently resolves module files. Download by module mode will be much faster.
- If you've enabled remove stale files (and folders), we'll now only scan files in each course folder.
- Now you'll be warned if you've downloaded incomplete file. It seems that canvas server will randomly cut down connection without any reason.

Thank you for using canvas_grab! In this version, we make some minor improvement. You may choose not to upgrade if you don't encounter the issues below.

- Now we will remove empty folders when removing stale files
- Sometimes download bar will appear in wrong position. We've fixed it.

If you have any question, have any advice, or want new features, feel free to create an issue at https://github.com/skyzh/canvas_grab/issues

- We can remove file in your download folder but not on Canvas for you. Enable this functionality by tweaking `SCAN_STALE_FILE` config.
- Files updated on Canvas will be downloaded correctly. Specifically, you'll encounter this bug when the teacher deleted the original file and re-uploaded one. Previously we introduced a bug that considers them as duplicated files.