Includes PHPDoc license tag in the file-level block with accompanying copyright notice.
Also added an AUTHORS file on the off chance of outside contributions
This required adding the "notes" column to the arsse_marks table and adding same as a target value in Database::articleMark()
The Context class was also adjusted to remove the possibility of false positives in some tests
- Backend functions for adding, listing, removing, and editing (renaming) labels currently implemented
- TTRSS functions for adding (fixes #96), removing (fixes #97), and renaming (fixes #98) labels currently implemented