Add new allegiances.json file listing each character's faction allegiances.

- Use this to enable assigning more than one faction per character along with metadata about where in the novel they belonged to each faction.
- Replaces "faction" attribute in characters.json which only lists one faction per character.
- Not finished making the changes to the data files yet, and the changes will break existing code so I am working in a separate branch until the code and views are updated to reflect this change to the data.
Add more data to allegiances.json.

- Change Xiahou Ying to the "Han" faction, as he predates the events of the novel.
- Change Cen Zhi to the "Other" faction to be consistent with the other Eight Paragons of Jiangxia.
Fix error where I mistook a reference to Lü Bu's wife as referring to Diaochan.
Add more data to allegiances.json.
Fix typo in chapters.json.
Fix incorrect person id appearing on page 156.
Add more data to allegiances.json.

Also switch Hu Miao to the Dong Zhuo/Li Jue/Guo Si faction.
Add remaining data to allegiances.json.
Remove left-over faction attributes from characters.json.
Fix some errors in allegiances.json.
Support multiple faction allegiances per character.

- Keep array of allegiance info in each Person object.
- Compute a "primary" faction for each character based on how frequently they appear on a page as a member of said faction. (May need to refine the logic behind this later.)
- Each character may now appear on more than one faction page in the UI if they are defectors (e.g. Cao Bao).
Add tests for allegiances.json data sanity.

Fix allegiance info for Feng Xu.
Tighten the graph up a bit, as some circles were going off the edge.
Get coappearance pages working with new allegiance stuff.
Have Diaochan enter Lü Bu's faction on the same page as he does.
Put Gongsun Zan in the Han faction until the alliance against Dong Zhuo.
Assign per-chapter factions for each character.

This allows e.g. Lü Bu to be shown in different faction colors in different chapter visualizations.
Assign some people to the Han faction at the beginning of the novel.
Get factions page and per-faction pages working with new allegiances data.