Feature Request: Sort and custom states #53

I love this extension. For my research, I do a lot of code reading, and this easy and non-destructive approach helps me a lot. I'd love to see two features that would help with organizing the notes.

1. The ability to sort by a note's line number, instead of chronologically by when a note as added
2. The ability to add custom states. Instead of Pending/Done I often need to categorize my annotations.

Thank you very much for all your work!