New release v3.0.0

[dyumanaditya]

Major changes:

• [x] Make unseen clause variables in node clauses take all possible nodes instead of just the neighbors
• [x] Restructure the way subsets are treated why grounding rules, make sure that the previous subsets are updated to take into account the changes from the new clause groundings
• [ ] Modify annotation function parameter to see what are the specific labels and nodes associated with each annotation
• [x] Update parallel core support, make sure it is threadsafe
• [x] Fix bug with interpretation dictionary not working with no timestep specification in pr.reason()
• [x] Fix issue where different variables are being grounded by the same constant.
• [x] Update Readme.md and add link to documentation
• [ ] Update the way we can delete nodes/edges (see ad-hoc-branch)
• [ ] Remove nested lists in grounding process
• [ ] Make sure not to add an edge if there is an edge that exists
• [x] Text facts
• [x] Make it simpler to input rules and facts
• [x] Fix bug with interpretation dict after reasoning (no timestep)
• [ ] UPDATE DOCS