Update README and to do list

Author: jstrieb

README.md

@@ -250,6 +250,7 @@ the application from the highest to lowest level.
     function object
 - [`src/global.css`](src/global.css) and [`public/*`](public/) – global
   stylesheet, favicons, etc.
+- [`test/*`](test/) – test suite and related functions
 
 ## Cool Code Highlights
 

todo.md

@@ -20,6 +20,7 @@
   - Formula draggy thing
   - Reformat for printing and export
   - Edit formulas in long text box at the top
+    - Formula inline edit textarea can grow and is visible above other cells
 - Settings window
   - Change colors
   - Change debounce save timeouts
@@ -42,7 +43,6 @@
   - Automatic indent
 - Formula processing
   - "symbols" in formulas
-  - References across sheets in formulas
   - Namespaced formula functions
 - Local storage
   - Save sheets