[docs/otfautohint_Notes.md] Add summary bullet point list into doc

docs/otfautohint_Notes.md

@@ -4,6 +4,27 @@
 originally written in C by Bill Paxton. That code was most recently distributed
 as "psautohint" in a PyPI package of the same name.
 
+Changes Summary:
+* [Name-Change] The name-change better reflects how hinted input is now published, 
+  and lets the new version coexist with the old version when needed.
+* [AFDKO Tools Updated] Other tools in AFDKO have been updated to call oftautohint 
+  instead of psautohint, and the dependency on the latter's repository has been removed.
+* [Stopping Psautohint Development] We expect to stop development of psautohint once
+  the 3.9.8 release is made.
+* [Improvements] The new code fixes a number of bugs and in our judgement produces 
+  better results on average. It also uses a slightly different encoding in
+  UFO glif files. Accordingly, users should expect that running the new code
+  results in many differences compared with psautohint, but this should be a one-time change.
+* [Variable CFF Hinting] The new code also supports hinting of variable CFF-based fonts,
+  including directly hinting a built CFF2 font. Glyphs that include overlap will typically 
+  be hinted close to how they would have been hinted with overlap removed.
+* [Hinting Time] Because psautohint was partly written in (very old) C code,
+   and otfautohint is written entirely in Python, the new code takes significantly
+   longer to hint an individual glyph. However, we have also enhanced otfautohint
+   to hint different glyphs on multiple CPU cores by default. As a result the tool
+   will be 5-8 times slower when running on a single core but will typically be
+   slightly faster when running on 8 cores.
+
 Most of the algorithms are unchanged but not all. Some notable differences are:
 
 1.  Because all code is now in Python there is no role for the `bez` charstring