print safe URLs: Avoid similar chars in doc ids

[cben]

Should avoid ambiguity of lowercase L, capital i and 1, and 0 / capital O. Switch from base 62 to smaller set e.g. http://tantek.pbworks.com/w/page/19402946/NewBase60? Not sure I like the _.

• [ ] test existing docs for ambiguity collisions
• [ ] restrict generated set
• [ ] decide on supporting alternate spelling e.g. O -> 0?

[cben]

https://en.wikipedia.org/wiki/Base58 - like NewBase60 but also omit 0 and _.

[cben]

implementation: https://github.com/ai/nanoid looks nice (can work with any alphabet)