Remove NOTES.txt (#1517)

I forgot to remove this in #1073 before merging.

NOTES.txt

@@ -1,39 +0,0 @@
-# Before Merging:
-* Remove the timing / existing-content information from view
-* Remove cr2-organization/
-
-# Plans for Later:
-
-## High Priority
-
-* Address slides that are too large for the aspect ratio, either by breaking
-  them up, shrinking them down, or some other creative solution.
-
-## Other Fixes
-
-* Can the segment headers (src/segname.md) be auto-generated, or done with a
-  macro? (#1415)
-  * Can these include timing information
-  * Can the per-day and overall-course sections also include timing info?
-
-* Can CI detect deletion of a slide without corresponding book.toml entry?
-  (#1417)
-* Simplify the GUI exercise (methods-and-traits)
-* Better examples for trait-bounds and impl trait, since students haven't yet
-  seen std traits
-* Traits slide should mention associated types, trait parameters, trait
-  "inheritance"
-* Improve iterator example (per suggestions from reader)
-* Modify `Interior Mutability` to use Mutex instead of Cell/RefCell, as noted
-  in the comment in that file.
-* Replace the health-statistics exercise, which really has little to do with
-  borowing. Maybe something that tempts students to use &mut self at the same
-  time as an exclusive reference to a field of self?
-* Talk about `ref` and `mut` modifiers in pattern matching
-* Add "recaps" at the beginning of each day
-* "9.5. Type Aliases: The example shows how to declare, but on how it looks in
-  practice is not clear enough (there is a use of one type alias but it's
-  hidden in a complex type). Ideally I would add some function signatures or
-  custom structs that showcase the cleanliness of this." (@deavid)
-* Cover trait objects after memory management, since they require some
-  understanding of Box.