Book improvements for 0.11.4

[Robotgiggle]

Based on #1134, but doesn't cover the meta-eval section since that isn't changing until 1.21.

• Proper definition for "hex" and/or "evaluatable" somewhere in the book
  • Change "list of patterns" to "list of iotas" (with additional clarification if necessary) since embedding allows other stuff in lists
• Remove the Influences section, move null and garbage descriptions into the main iota list in 101
• Overhaul the Primer on Vectors section to actually explain vectors instead of just linking to Psi's explanation
• Reorganize and partially rewrite escapes section
  • Clarify functionality of Contemplation vs Consideration
  • Adjust Further Notes to better describe Consideration doubling

Does not include anything for #737 since that was already handled by #862.

Note: when removing the link to the Influences entry from the Escaping Patterns entry, in en_us I changed the text that previously contained the link from "influences" to "special patterns". However, I was unable to do this for the other languages, so the link is gone but the text still has whatever translation was used for "influences" - this will probably need to be adjusted by whoever handles the relevant translations.

[IridescentVoid]

Mostly looks good to merge.

[IridescentVoid]

Also, we might want a changelog entry for these changes.